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Review

Nickel Selenides in Electrocatalysis: Coupled Formate and Hydrogen Production Through Methanol Oxidation Reaction

by
Hong Tu
1,
Yan Zhong
1,
Zhihao Yang
1,
Caihong Zhang
1,
Yi Ma
2,
Yong Zhang
2,
Ning Jian
2,
Huan Ge
2 and
Junshan Li
2,*
1
School of Intelligent Manufacturing, Sichuan University of Arts and Science, Dazhou 635000, China
2
Institute for Advanced Study, Chengdu University, Chengdu 610106, China
*
Author to whom correspondence should be addressed.
Catalysts 2025, 15(6), 516; https://doi.org/10.3390/catal15060516
Submission received: 23 April 2025 / Revised: 20 May 2025 / Accepted: 21 May 2025 / Published: 23 May 2025
(This article belongs to the Special Issue Catalysis for Energy Storage and Batteries)
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Abstract

:
The hydrogen economy, associated with electrochemical water splitting, represents a promising pathway to mitigate reliance on fossil fuels. However, the efficiency of this process is constrained by the sluggish oxygen evolution reaction (OER) at the anode, with low commercial interests of the produced oxygen. As a promising solution, OER can be replaced with the methanol oxidation reaction (MOR), which not only accelerates the hydrogen evolution reaction (HER) but also yields valuable formate as a product, depending on the nature of the anode electrocatalysts. In this context, nickel selenides have emerged as highly efficient and cost-effective electrocatalysts due to their rich compositional diversity, tunable electronic structures, and superior conductivity. Additionally, nickel selenides exist in multiple stoichiometric and nonstoichiometric phases, and also in the engineering versatility for optimizing catalytic MOR performance. This review comprehensively presents the design principles of electrocatalysts, provides a strategy for the optimization of performance, and discusses the mechanistic understanding of nickel selenide-based electrocatalysts for coupled HER and MOR systems, particularly focusing on the MOR. By bridging fundamental insights with practical applications, it additionally highlights the latest advancements in their catalytic MOR performance, offering insights into their potential for future energy and chemical applications.

1. Introduction

The growing global energy demand and the depletion of fossil fuel resources, coupled with severe environmental pollution, have intensified the search for clean and renewable energy alternatives [1]. Among these, hydrogen is widely recognized as a promising energy carrier due to its clean and sustainable nature, especially when produced from water using renewable energy sources [2,3,4]. Water electrolysis, a key process for hydrogen production, involves two half-reactions: the hydrogen evolution reaction (HER) at the cathode and the oxygen evolution reaction (OER) at the anode [5,6,7,8]. However, the OER suffers from a high overpotential, necessitating significant energy input and robust equipment to achieve practical current densities [9]. A promising strategy to address this challenge is replacing the OER with the small organic molecule oxidation reaction (OOR), as shown in Figure 1a.
In electrochemistry, the thermodynamic potential for the OER during water splitting is typically 1.23 V [13]. This value is substantially higher than that of most organic oxidation reactions. For example, the oxidation of methanol requires only 0.103 V, urea 0.37 V, hydrazine 0.33 V, ammonia 0.06 V, and glucose 0.05 V [14]. From a thermodynamic perspective, the replaced OOR represents a promising alternative to water splitting OER [15]. As primary alcohols, nucleophilic molecules contains hydroxyl (-OH) groups in the structure [14]. As shown in Figure 1b, the nucleophilic oxidation reaction (NOR) allows nucleophiles to be oxidized to their carboxylic acid products. The oxidation of alcohols to carboxylic acids is generally believed to follow the conversion of the alcohol (R−OH, where R represents an alkyl or substituted alkyl group) into an oxygen-rich carboxylic acid. This transformation to carboxylic acids is a key step in various chemical and industrial applications, as can be found in our and other investigations [16,17,18,19,20,21,22,23,24,25]. In particular, the usage of methanol to replace the OER for boosting HER could reduce the energy by 20–40% compared to traditional water electrolysis [26,27].
Among the nucleophilic molecules, methanol stands out due to its affordability, ease of transportation, and widespread availability [28]. In alkaline media, methanol is usually electrochemically converted into value-added formic acid, and finally exists in the form of formate. The current formic acid demand is up to over 1 million tons per year, and the most common method involves the reaction of methanol with carbon monoxide to produce formic acid [29,30,31]. However, this production process highly relies on fossil-derived CO, is energy-intensive, and produces byproducts. Compared with the traditional ways, the methanol-assisted water splitting system holds several advantages over traditional and industrial methods, including enhanced energy efficiency, cost savings, increased product rate, higher profit, and improved safety (Figure 1c).
To demonstrate the economic and environmental advantages of the coupled MOR and HER system, Meng et al. evaluated its profitability and global warming impact. Specifically, the economic analysis considers factors such as initial plant investment (covering electrolysis and distillation), operational and maintenance costs, government tax, and other practical expenses [12]. Due to the high initial investment, the cumulative net profit (total earnings minus costs) remains negative in the early years. As shown in Figure 1d, as catalysts are refreshed and equipment are regularly maintained, the plant achieves a positive net profit after year four at a current density of 75 mA cm−2. Additionally, a life cycle assessment accounts for the entire life cycle from raw material extraction to waste disposal, evaluating the environmental impact of the coupled system compared to water splitting cells. As shown in Figure 1e, the coupled system significantly reduces CO2 emissions, highlighting its potential for sustainable energy production [12]. To this end, the efficient and cost-effective MOR electrocatalysts is the main focus.

2. Electrocatalysts Based on Nickel Selenides

The coupled system based on MOR and HER hold significant industrial potential for the simultaneous production of formic acid and hydrogen. For it to become commercially viable, the development of high-performance MOR electrocatalysts based on earth-abundant materials is essential. Previous studies have shown that Ni-based electrocatalysts, when combined with earth-abundant elements, can effectively accelerate MOR at a potential higher than 1.23 V vs. RHE [32,33,34]. It should be noted that the MOR can also take place on Pt- or Pd-based catalysts at 0.6~0.8 V vs. RHE, in the field of fuel cells (FCs) [35,36,37,38,39,40,41].
Among these, nickel selenides (Ni-Se) have emerged as particularly promising candidates due to their excellent electrical conductivity, tunable electronic structures, and strong synergistic interactions between Ni and Se [42,43,44,45,46,47]. As shown in Figure 2, nickel selenides exhibit a series of common structures (NiSe2, NiSe, Ni3Se4, Ni3Se2) with increasing Ni/Se ratio, each with distinct electronic and structural properties that influence their catalytic performance. In addition, other Ni-Se compounds, such as NiSe3 and Ni5Se4, are not common and less studied in the field of electrocatalysis.
One of the key advantages of nickel selenides is the synergistic interaction between nickel and selenium. Nickel’s electron configuration (3d84s2) enables multiple valence states, making it highly reactive in electrochemical processes. The addition of selenium further enhances catalytic properties by modifying the electronic structure and improving charge transfer efficiency. Selenium’s energy levels align closely with nickel’s 3s and 3p orbitals, allowing for strong metal–chalcogen bonding interactions [42,48,49]. This unique interaction improves electron transport properties, reduces charge transfer resistance, and enhances catalytic efficiency. This unique synergy contributes to both improved activity and long-term durability [48]. Under alkaline conditions, Ni-based catalysts tend to form in situ NiOOH species, which act as active centers for oxidation reactions. Additionally, the presence of residual or adsorbed SeOx oxyanions has been observed to enhance electrochemical performance, although their precise role in selective methanol oxidation remains an area of ongoing investigation [50,51,52].
Despite these advantages, the design and engineering of nickel selenides for MOR have received relatively little attention. Given their promising catalytic properties, further exploration of Ni-Se-based materials for methanol electro-oxidation could unlock new opportunities for integrated hydrogen production. A systematic review and in-depth analysis of the progress in Ni-Se-based electrocatalysts are therefore crucial for advancing research in this area. Thus, in the following, recent advancements in material design, in situ characterization techniques, and hybrid catalyst development in MOR-assisted water splitting will be presented.

3. Recent Advances

Electrocatalytic performance is often influenced by the combination or integration of multiple components, where the synergistic effect exceeds the sum of their individual contributions. These components can include various crystal planes, dopants, morphologies, structures, and support materials, all of which play a crucial role in optimizing catalytic activity [53]. Given the tunable nature of MOR performance, this section will present various strategies, not only providing insights into the key design principles that govern electrocatalyst performance, but also offering a comprehensive understanding of how different approaches contribute to improved activity, stability, and overall efficiency. Thus, the following summary highlights key findings from recent studies on the engineering of Ni-Se and its derived electrocatalysts to enhance MOR performance (Table 1).
To compare MOR performance for different Ni-Se phases, a series of Ni-Se electrocatalysts were synthesized via a one-step hydrothermal method by mixing nickel/water and selenium/hydrazine precursor solutions, followed by heating at 180 °C for 16 h, as shown in Figure 3a. By adjusting the nominal Ni/Se ratios to 1/1, 3/4, and 1/2, distinct NiSe, Ni3Se4, and NiSe2 phases were obtained. The electrocatalytic performance toward MOR was evaluated in 1 M KOH with and without 1 M methanol. In the presence of methanol, a rapid increase in current density was observed above ~0.4 V vs. Hg/HgO, corresponding to MOR (Figure 3b). Compared to the alkaline medium alone, the introduction of methanol significantly enhanced the MOR current density, with Ni3Se4 exhibiting the highest activity. At 0.6 V vs. RHE, net MOR current densities of 84.3, 149.8, and 103.8 mA cm−2 were recorded for NiSe, Ni3Se4, and NiSe2, respectively (Figure 3c). Figure 3d presents the long-term chronoamperometry (CA) for Ni3Se4-based electrodes at 0.6 V vs. Hg/HgO, delivering an initial current density of 95.5 mA cm−2, and stabilizing at 73.6 mA cm−2 after 20 h. Further ion chromatography (IC) analysis confirmed a methanol-to-formate Faradaic efficiency of 95.7% (Figure 3e). DFT calculations revealed that the Ni3Se4(002) surface exhibited the most favorable methanol adsorption energy (ΔG = −1.16 eV), facilitating initial CH3OH activation. Moreover, the Ni d-band center (εd) in Ni3Se4 (−1.10 eV) was closer to the Fermi level than in NiSe (−1.60 eV) and NiSe2 (−1.38 eV), enhancing electronic conductivity and electron transfer (Figure 3f). These results highlight Ni3Se4 as the most efficient Ni3Se4 phase for MOR, benefiting from optimized adsorption energetics and electronic structure [54].
In another study, a three-dimensional NiSe2 nanosheet-based electrocatalyst was synthesized via a simple solvothermal method followed by annealing. The catalyst demonstrated excellent electrocatalytic performance, achieving a current density of 21.58 mA cm−2 at 1.70 V vs. RHE with a Tafel slope of 39.14 mV dec−1. Additionally, it exhibited strong resistance to poisoning and maintained stable performance over 3600 s of continuous operation [55].
Heteroatom doping is a powerful strategy for enhancing the intrinsic activity of catalysts [56,57,58]. By introducing exogenous elements into the bulk material, the electronic and crystal structures can be systematically tailored. Due to differences in atomic radii, heteroatom doping induces lattice dislocations and local electron redistribution, which in turn alters the adsorption and desorption behavior of reaction intermediates. As a result, the catalytic performance can be effectively optimized. In one of our recent studies, nickel–iron diselenide nanorods (NRs) were synthesized across their full compositional range (Ni1−xFexSe2) using a two-step solution-based approach, as schematically presented in Figure 4a. The process involved dissolving Ni and Fe acetylacetonates with Se powder in a mixture of ethanedithiol (EDT) and oleylamine (OAm), followed by reaction at 220 °C in OAm. The resulting nanoparticles exhibited an elongated morphology, averaging ~10 nm in width and ~50 nm in length. Figure 4b shows that MOR activity was particularly enhanced for Ni0.75Fe0.25Se2 than the NiSe2 electrodes, with FeSe2 showing nearly no MOR activity. The long-term stability was tested by means of CP recorded at a current density of 50 mA cm−2 for the optimized composition, as shown in Figure 4c. As can be seen clearly, the initial voltage was 1.46 V, followed by a slight increase of approximately 50 mV after 50,000 s of testing. At the end of the CP test, a total of 1.27 mmol of formate was electrochemically generated by delivering a charge of 500 C, corresponding to a Faradaic efficiency of 98.2% and a production rate of 0.47 mmol cm−2 h−1. The Fe doping in the NiSe2 structure introduced additional electronic states near the Fermi level of Ni0.75Fe0.25Se2, enhancing charge transfer and transport properties. Moreover, the presence of Fe atoms significantly influenced the electronic structure of neighboring Ni sites, contributing to the reduced overpotential and improved catalytic performance [59].
Typically, cobalt doping in NiSe has been explored to enhance its electrocatalytic performance for the MOR. Souradip et al. reported that a series of (Ni1−xCoxSe) nanocatalysts were synthesized by incorporating cobalt nitrate hexahydrate (x = 0.01–0.1) without altering other synthesis conditions. Figure 4d presents their XRD patterns, confirming the formation of a pure hexagonal NiSe phase (P63/mmc) without secondary phases such as Ni3Se4, NiSe2, NiO, or SeO2. As shown in Figure 4e, further HRTEM proves the successful Co doping in the structure. Electrochemical studies revealed that Co doping influenced the MOR onset potential and catalytic activity, as presented in Figure 4f. While CoOOH in CoSe was not sufficient to initiate MOR at lower potentials, the incorporation of Co into NiSe led to a reduction in onset potential and faster formation of Ni(Co)OOH active species. Among the tested compositions, Ni0.9Co0.1Se exhibited the highest catalytic activity, achieving a peak current density of 185 mA cm−2 at 1.65 V vs. RHE and a mass activity of 3775 mA mg−1 (Figure 4g). However, significant Ni content remained necessary for maintaining efficient MOR performance, particularly at higher overpotentials. DFT calculations provided insights into the promotional effect of Co doping, as shown in Figure 4h,i. The introduction of Co(II) facilitated the transformation of Ni(OH)2 to hypervalent Ni(Co)OOH at a lower potential compared to NiOOH, enhancing methanol adsorption and charge transfer. Importantly, Co doping did not alter the MOR mechanism but increased the density of redox-active sites and improved electron transfer. Both experimental and theoretical analyses confirmed that Ni0.9Co0.1Se exhibited superior catalytic activity, achieving 80–100% product conversion with a FE of 80–95% [60].
In another study, a MOF-derived Ni- and Co-doped iron selenide (NiCoFeSe) electrocatalyst was synthesized in the form of hexagonal nanorods, exhibiting exceptional electrocatalytic activity for the HER, OER, and UOR. The catalyst achieved low overpotentials of 220 and 275 mV for HER, 230 and 330 mV for OER, and 210 and 300 mV for MOR at current densities of 50 and 100 mA cm−2, respectively. Furthermore, a wireless, flexible, and rigid photovoltaic–electrochemical (PV-EC) device was developed using NiCoFeSe as both the anode and cathode, attaining a notable solar-to-hydrogen efficiency of 11.1%. Additionally, an anion exchange membrane (AEM) water electrolyzer incorporating NiCoFeSe as both electrodes demonstrated a high current density of 1.07 A cm−2 at 1.85 V, a cell efficiency of 69.67%, and an energy consumption of 47.85 kWh per kg of hydrogen produced [61].
Elements like Se, S, and P would be reconstructed as surface oxyanions formed on the electrocatalysts in alkaline media at proper external potential, leading to higher performance. To study the role of the oxyanion-doped (P, S, or Se) effect for enhancing MOR in Ni-based materials, a series of amorphous Ni oxyhydroxide (NiOOH-TOx, T = P, S, or Se) electrocatalysts were synthesized [62]. The process involves in situ surface reconstruction of Ni-metalloid (NiTx) precursors through electrochemical activation, as presented in Figure 5a. After surface reconstruction, the DFT optimized different oxyanion-doped NiOOH and the pristine NiOOH structures are illustrated in Figure 5b. In addition, the local coordination environment of the oxyanion doping was extensively investigated by XAFS. As shown in Figure 5c, the surface oxidation was further supported by Se 3d XPS analysis, which showed a decrease in elemental Se content and an increase in Se-O bonds after reconstruction. Electrochemical performance evaluation showed that NiPx-R required only 1.49 V to achieve a current density of 100 mA cm−2 for MOR in 1.0 M KOH with 0.5 M methanol, a negative shift of 193 mV compared to OER, as plotted in Figure 5d. As can be seen in Figure 5e, among the three catalysts, NiPx-R exhibited the largest potential gap between MOR and OER and the lowest onset potential, achieving 400 mA cm−2 at 1.4 V, with 90 and 117 mV lower than NiSx-R and NiSex-R, respectively. These results highlight oxyanion-doped NiOOH as a highly efficient MOR catalyst with significantly reduced overpotential compared to previously reported Ni-based systems [62].
A controllable Se coating strategy was developed for nickel selenide (Ni3Se4) NPs to enhance their MOR performance. Upon exposure to an alkaline environment, the surface Se layer was partially transformed into selenium oxides (SeOx), which played a crucial role in optimizing electrocatalytic activity. Figure 5f demonstrates that Ni3Se4 NPs with an 8.1% amorphous Se coating (a-Se@NS-8.1%) exhibited exceptional MOR activity, achieving current densities of 100 and 160 mA cm−2 at 1.5 and 1.6 V, respectively. Additionally, this optimized catalyst with proper Se coating also displayed remarkable stability, maintaining a current density of 128 mA cm−2 after 18 h of continuous operation at 1.6 V, outperforming other Ni3Se4-based electrocatalysts (Figure 5g). Further IC confirmed a high methanol-to-formate selectivity with a Faradaic efficiency of 98%. Surface hydrophilicity, a critical factor influencing electrolyte infiltration and catalytic performance, was assessed via contact angle measurements arising from the different contents of Se coating. As shown in Figure 5h, the a-Se@NS-8.1% catalyst exhibited an initial contact angle of 27.8°, which rapidly decreased to 16.6° within 500 ms, indicating enhanced hydrophilicity. While a higher amorphous Se content (22.3%) further improved hydrophilicity (23.8° to 11.73° within 500 ms), it did not translate into the best MOR performance, highlighting the complex interplay of multiple factors in catalytic activity. DFT calculations suggested that the presence of SeOx reduced methanol dehydrogenation, contributing to improved catalytic efficiency. This study underscores the importance of surface Se engineering in optimizing the electrocatalytic performance of Ni-Se-based materials for MOR [63].
Heterostructure engineering has emerged as a useful strategy to enhance the performance of Ni-based electrocatalysts for MOR by optimizing electronic properties, increasing active sites, and improving reaction kinetics [64,65,66,67]. For example, Peng et al. prepared a heterostructured NiSe/MoSe2 (NMS) electrocatalyst for the co-catalysis of MOR and HER [68]. This designed NMS heterostructure was synthesized via a selenation process, forming nanowires with embedded NiSe NPs, as presented in Figure 6a. The heterointerface between MoSe2(002) and NiSe(101) was selected to construct the model based on the observed distorted domain. Figure 6b presents the optimized structural model of this heterointerface compared with MoSe2(002) and NiSe(101) surfaces. As can be seen in the individual MoSe2(002) and NiSe(101) structures, a noticeable atomic rearrangement occurs near the interface, as highlighted by the dotted and dashed rectangles. Additional TEM and HRTEM analyses also confirmed this heterostructure, as can be seen in Figure 6c. Specifically, the lattice spacing of 0.65 nm and 0.27 nm corresponded to the MoSe2(002) and NiSe(101) planes, respectively. Figure 6d demonstrates that the MOR required a 15% lower potential than the OER at 100 mA cm−2. DFT calculations further revealed that the heterointerface facilitated enhanced methanol adsorption and reduced energy barriers for key reaction steps, as presented in Figure 6e. The free energy for the first C–H bond cleavage was significantly lower for NMS (0.21 eV) compared to pure NiSe (0.76 eV) and MoSe2 (1.66 eV), highlighting the superior catalytic performance of the heterostructure. These findings demonstrate that the synergistic interactions at the NiSe/MoSe2 heterointerface optimize electronic structure and reactant binding, significantly enhancing MOR activity for efficient methanol-assisted hydrogen production. Long-term stability of this electrocatalyst for the overall reaction at 1.8 V for 24 h was presented in Figure 6f, showing excellent stability. The integrated system powered by solar cells with an output voltage of 1.5 V is presented in Figure 6g,h, demonstrating significant energy savings compared to conventional water electrolysis [68].
To check the effectiveness of heterojunction electrocatalysts for integrating the HER and MOR system, Hu et al. developed MnSe/NiSe composite material. Serving as a bifunctional catalyst required electrolytic potentials of 1.53 V and 1.79 V to attain current densities of 10 mA cm−2 and 50 mA cm−2 in alkaline media, respectively. These potential values with the presence of methanol are distinctly lower than those needed for the overall water splitting process [69].
In another case of CeO2−Ni2Co1Sex-NC-450 catalysts, the synergistic interaction among NiSe2, CoSe2, and CeO2 modulates the electronic structure, enhancing stability and generating additional active sites. The unique 3D architecture of NiSe2/NC-450, with N-doped carbon serving as a conductive carrier facilitates efficient electron transport. Furthermore, the selenization process at 450 °C optimizes structural arrangement and increases Ni and Se content, leading to superior MOR performance. As a result, this catalyst achieves a high peak current density of −164.68 mA cm−2 and a low oxidation potential of −1.33 V at 10 mA cm−2. Similarly, the MnSe/NiSe heterostructure leverages electronic modulation induced by Ni incorporation, optimizing the adsorption of water and methanol molecules. This results in the formation of dual active sites at the MnSe/NiSe interface, significantly enhancing both hydrogen evolution and methanol oxidation performance. The MnSe/NiSe catalyst exhibits a low overpotential of 142 mV at 10 mA cm−2 in MOR and a small Tafel slope of 82.0 mV dec−1, indicating favorable reaction kinetics [70].
Table 1. Summary of MOR performance on recent Ni-Se-based electrocatalysts in alkaline media.
Table 1. Summary of MOR performance on recent Ni-Se-based electrocatalysts in alkaline media.
ElectrocatalystsSynthesis MethodMorphologyElectrolytePerformance
mA cm−2 @ RHE		ProductFEReference
Ni3Se4hydrothermalnanoparticles1 M KOH + 1 M methanol149.8 @ 1.5Vformate95.7%[54]
NiSe2solvothermal + annealing3D nanosheets1 M KOH + 1 M methanol5.6 @ 1.7Vn.a.n.a.[55]
Ni0.75Fe0.25Se2ink solutionnanoparticles1 M KOH + 1 M methanol53.5 @ 1.5Vformate99%[59]
Ni0.9Co0.1Sesolutionnanosheets1 M NaOH + 1 M methanol185 @ 1.65Vformate84%[60]
NiPx-Ranionization + reconstructionnanosheets1 M NaOH + 0.5 M methanol~200 @ 1.6Vformaten.a.[62]
a-Se@NS-8.1%hydrothermalnanoparticles1 M KOH + 1 M methanol160 @ 1.6Vformate98%[63]
NiFe MOF@NiSexsolvothermalnanosheets1 M KOH + 0.8 M methanol~500 @ 1.65Vn.a.n.a.[71]
Carbon nanofibers@NiSecolloidalnanocrystals1 M KOH + 1 M methanol~300 @ 1.6Vformate97.9%[72]
NiCo2O4/NiCoSe2hydrothermalflower-Like1 M KOH + 0.5 M methanol~130 @ 1.5Vn.a.n.a.[73]
MnSe/NiSesolvothermalhydrangea-like1 M KOH + 0.07 M methanol50 @ 1.79Vn.a.n.a.[69]
NiSe/MoSe2/CChydrothermalnanowire1 M KOH + 1 M methanol100 @ 1.38Vformaten.a.[68]
CeSe/Co3Se4@NiSe-NFelectrodepositionflower-Like1 M NaOH + 0.5 M methanol~135.6 @ 1.45Vformaten.a.[74]
NiSe2/NCselenization3D architecture1 M KOH + 0.5 M methanol~164.5 @ 1.7Vn.a.n.a.[75]
CeO2-Ni2Co1Seannealingnanosheets1 M KOH + 0.5 M methanol~175 @ 1.7Vn.a.n.a.[76]
NiSe2@NiAlcoprecipitation + annealingnanoparticles1 M KOH + 0.5 M methanol~200 @ 1.7Vn.a.n.a.[77]
NiSe/carbon nanotubecolloidal3D network1 M KOH + 1 M methanol~345 @ 1.62Vformate95%[78]
NiSe/Ni foilin situ growthnanowire1 M KOH + 0.5 M methanol~130 @ 1.55Vn.a.n.a.[79]
RGO/NiSe@P-NMPysolution2D sheet-like0.5 M KOH + 1 M methanol~50 @ 1.5Vn.a.n.a.[80]
NiSe/RGOselenization + annealingnanoparticles1 M KOH + 0.5 M methanol~56 @ 1.35Vn.a.n.a.[81]
Note: n.a. (not available).
Catalysts 15 00516 g006
Figure 6. (a) Schematic drawing for synthesis of bifunctional NMS/CC electrocatalyst. (b) Top view of simulated NiSe(101)/MoSe2(002) heterointerface and individual MoSe2(002) and NiSe(101) surfaces (brown color represents Se, cyan represents Mo, and blue represents Ni). (c) HRTEM image of NMS nanowire. (d) Polarization LSV curves recorded in 1 M KOH with 0.5 M methanol within potential range of 1.0–1.7 V vs. RHE. (e) DFT calculated free energy profiles for methanol-to-formate process. (f) Long-term stability of this developed electrocatalysts for overall reaction at 1.8 V for 24 h. (g,h) Photograph of overall reaction system powered by solar cell and also of anode and cathode. Reprinted from ref. [68]. Copyright 2022, The Royal Society of Chemistry. (i) HRTEM image of as-synthesized h-NiSe/CNTs. (j) LSV curves of h-NiSe/CNTs/CC, NiSe-m-CNTs/CC, IrO2/CC, NiSe/CC, and CNTs/CC anodes in 1 M KOH with 1 M methanol, along with LSV curve of h-NiSe/CNTs/CC anode in 1 M KOH. (k,l) Potential-dependent in situ Raman spectra of h-NiSe/CNTs anode recorded under multi-potential steps in 1 M KOH and 1 M KOH with 1 M methanol. Reprinted from ref. [78]. Copyright 2018, Wiley-VCH GmbH.
Figure 6. (a) Schematic drawing for synthesis of bifunctional NMS/CC electrocatalyst. (b) Top view of simulated NiSe(101)/MoSe2(002) heterointerface and individual MoSe2(002) and NiSe(101) surfaces (brown color represents Se, cyan represents Mo, and blue represents Ni). (c) HRTEM image of NMS nanowire. (d) Polarization LSV curves recorded in 1 M KOH with 0.5 M methanol within potential range of 1.0–1.7 V vs. RHE. (e) DFT calculated free energy profiles for methanol-to-formate process. (f) Long-term stability of this developed electrocatalysts for overall reaction at 1.8 V for 24 h. (g,h) Photograph of overall reaction system powered by solar cell and also of anode and cathode. Reprinted from ref. [68]. Copyright 2022, The Royal Society of Chemistry. (i) HRTEM image of as-synthesized h-NiSe/CNTs. (j) LSV curves of h-NiSe/CNTs/CC, NiSe-m-CNTs/CC, IrO2/CC, NiSe/CC, and CNTs/CC anodes in 1 M KOH with 1 M methanol, along with LSV curve of h-NiSe/CNTs/CC anode in 1 M KOH. (k,l) Potential-dependent in situ Raman spectra of h-NiSe/CNTs anode recorded under multi-potential steps in 1 M KOH and 1 M KOH with 1 M methanol. Reprinted from ref. [78]. Copyright 2018, Wiley-VCH GmbH.
Catalysts 15 00516 g006
Another example, the CeSe/Co3Se4@NiSe-NF composite, features a highly porous nanostructure that provides abundant electroactive sites and facilitates electrolyte ion transport, thereby improving overall electrochemical performance. This catalyst demonstrates excellent stability in both MOR and HER, maintaining a current density of 10 mA cm−2 at a low cell voltage of 1.45 V (vs. RHE) for at least 20 h in a two-electrode methanol-assisted water electrolysis system. Furthermore, the CoSe-0.2/NiSe-NRs/NF catalyst exhibits strong OER stability in alkaline electrolytes, attributed to the formation of NiOOH/CoOOH, which ensures structural integrity during cycling. The presence of well-crystallized β-NiOOH during the OER process further enhances catalyst durability, ultimately benefiting MOR performance in systems involving both reactions [74]. To further enhance the MOR performance, flower-Like NiCo2O4/NiCoSe2 exhibited a high MOR current density of 130 mA cm−2 and low onset potential. Additionally, these developed heterostructures can be efficient electrodes with high energy density for supercapacitors [73].
Another investigation was made on CNFs@NiSe core/sheath nanostructures, demonstrating highly selective conversion of methanol into valuable formate. Specifically, the production rate of formate remained almost constant at 8.98 mmol L−1 h−1. After 20 h of electrocatalysis, the concentration of formate reached 179.78 mmol L−1, and a high Faradaic efficiency (FE) of 98% was achieved at the anode. The MOR significantly enhanced the production of hydrogen at the cathode, with hydrogen generation rate reaching 35.67 × 10−8 mol s−1, which is 7.5 times higher than that in the absence of methanol. As a result, the energy consumption for harvesting clean energy was substantially reduced. Furthermore, density functional theory (DFT) calculations were conducted to delve deeper into the high selectivity of methanol conversion to formate. The calculations revealed that the conversion of methanol to formic acid (formate) is thermodynamically advantageous on the uniquely exposed NiSe (102) facets [72]. Heterostructure and interface engineering in Ni-Se-based electrocatalysts significantly enhance MOR performance by promoting charge transfer, increasing active site density, optimizing reaction kinetics, and improving catalyst stability.
The choice of support material plays a crucial role in enhancing the performance of electrocatalysts by improving conductivity, stability, and active site exposure [82]. Different types of supports can significantly influence electron transfer, mass transport, and catalyst durability. Materials such as nitrogen-doped carbon (NC), graphene, carbon nanotubes (CNTs), and reduced graphene oxide (RGO) provide excellent electrical conductivity and high surface area. These supports facilitate fast electron transfer and enhance the dispersion of active materials, leading to improved activity.
In a recent study, a highly active electrocatalyst composed of hollow NiSe nanocrystals heterogenized with carbon nanotubes (h-NiSe/CNTs) was developed via a facile one-pot synthesis. This nanostructured hybrid features monodispersed NiSe spherical nanocrystals (15–20 nm) within a CNT network (~10–15 nm in diameter), with a well-defined hollow interior and a shell thickness of ~5 nm. As shown in Figure 6i, structural analysis confirmed that the NiSe lattice fringes corresponded to the (101) and (102) planes of hexagonal Sederholmite NiSe, while the CNTs exhibited the (002) facets of graphitized carbon. As shown in Figure 6j, the electrochemical investigations demonstrated the superior performance of h-NiSe/CNTs for the MOR over the OER. Further CA tests at 1.62 V (vs. RHE) for over 20 h revealed excellent durability and selectivity in methanol upgrading to formate. Figure 6k,l presents the in situ Raman spectroscopy in KOH with or without methanol, further elucidating the reaction mechanism. As can been seen, the formation of Ni-OCH3 intermediates via a O-H activation pathway facilitated by Ni-OOH species. The Raman signals of Ni-OOH rapidly disappeared upon methanol introduction, indicating its preferential consumption in methanol activation rather than OER. DFT calculations revealed that the electronic structure of NiSe could be modulated by surface hydroxylation/oxidation, with SeOx species and Ni-OOH synergistically tuning the Ni d-band center. This optimized electronic environment enabled selective methanol oxidation while suppressing overoxidation to CO2. The 3D h-NiSe/CNTs network further enhanced mass and electron transport, leading to a high and stable current density (~345 mA cm−2) with a Faradaic efficiency exceeding 95%. These findings underscore the potential of h-NiSe/CNTs as an efficient electrocatalyst for sustainable methanol valorization and energy-efficient hydrogen co-generation [78].
Other supports were also adopted to enhance MOR performance. Fu et al. developed carbon nanofiber-supported NiSe (CNFs@NiSe) core/sheath nanostructures as highly robust and stable electrocatalysts for the selective electro-oxidation of methanol to value-added formate [72]. These electrocatalysts demonstrated excellent performance, achieving a high current density of 100 mA cm−2 at a remarkably low potential of 1.43 V (vs. RHE), which is 220 mV lower than the oxygen evolution reaction (OER) potential at the same current density. The CNFs@NiSe catalyst maintained a nearly constant formate production rate of 8.98 mmol L−1 h−1, reaching a final concentration of 179.78 mmol L−1 after 20 h of continuous electrocatalysis. Moreover, the process exhibited a high FE of 97.9% at the anode, highlighting its exceptional selectivity and energy efficiency. These findings underscore the potential of CNFs@NiSe as an effective electrocatalyst for sustainable methanol upgrading and energy-efficient hydrogen co-generation [72].
Furthermore, the incorporation of nitrogen-doped carbon as a support significantly improves the conductivity of NiSe-based catalysts. For example, in 3D nickel diselenide architectures grown on nitrogen-doped carbon (NiSe2/NC-450), the N-doped carbon serves as a conductive framework, accelerating electron transport and generating more active sites. This results in outstanding MOR activity, achieving a high peak current density of −164.68 mA cm−2 and a low oxidation potential of −1.33 V at 10 mA cm−2. Similarly, reduced graphene oxide (RGO) serves as an effective support material. In NiSe/RGO-550 nanoparticles, the presence of RGO enhances electrical conductivity and facilitates the diffusion of active species. The selenization process further increases the number of active sites, leading to a lower onset potential (1.35 V vs. RHE) and a higher peak current density (59.84 mA cm−2) compared to Ni-based precursors [75].
Introducing additional metal selenides or oxides enhances catalytic activity through synergistic interactions. In CeO2-Ni2Co1Sex-NC-450 catalysts, the combination of NiSe2, CoSe2, and CeO2 modulates the electronic structure, increases stability, and generates additional active sites. This material exhibits remarkable MOR performance, with a maximum current density of ~175 mA cm−2 and an oxidation potential of 1.291 V at 10 mA cm−2 [76]. Another example, RGO/NiSe@P-NMPy, benefits from the introduction of a polymerized reduced carbon sheet (P-NMPy), which enhances methanol oxidation activity and CO resistance. This electrocatalyst achieves a lower oxidation potential (0.1 V), a higher current density (127 mA cm−2), and excellent stability in alkaline conditions [80].
Supports like NiAl foam can introduce additional catalytic functions through electronic interactions. In the synthesis of 4NiAlSe-450, where NiSe2 is grown in situ on NiAl layered double hydroxide, 450 °C is identified as the optimal selenization temperature. This temperature preserves the layered structure and nanoparticle morphology, leading to high MOR activity and durability. The catalyst operates at 1.37 V vs. RHE at 10 mA cm−2 and maintains stable methanol oxidation for over three hours. Similarly, NiSe2/NC catalysts prepared at 450 °C exhibit a well structured 3D architecture with higher Ni and Se content, outperforming catalysts synthesized at other temperatures [77].
In conclusion, the engineering of supported NiSe electrocatalysts through strategic material selection, morphological tuning, synergistic component integration, and controlling other parameters effectively enhances their MOR performance. Together, the above strategies provide a powerful platform for designing next-generation electrocatalysts with superior activity, selectivity, and stability.

4. Conclusions and Outlook

This review highlights the advancements in Ni-Se-based electrocatalysts with a particular focus on MOR-assisted water splitting. The rational design of these electrocatalysts has led to notable improvements in catalytic efficiency, stability, and cost-effectiveness. However, despite these achievements, challenges remain in understanding the catalytic mechanisms, enhancing durability, and achieving large-scale implementation.
A deeper understanding of the active sites, surface transformations, and the role of selenium species during electrocatalysis is crucial. The integration of in situ characterization techniques, such as in situ Raman and XAFS, with DFT calculations can provide valuable insights into reaction pathways and surface dynamics, aiding in the rational design of next-generation catalysts.
To further enhance the performance of Ni-Se-based catalysts, innovative strategies such as defect engineering, heteroatom doping (i.e. Ni0.75Fe0.25Se2), phase modulation (NixSey), and heterostructure construction should be adopted. Combining multiple modification strategies can create synergistic effects, optimizing electronic properties and catalytic efficiency. Additionally, ensuring structural integrity and stability under operating conditions is essential for practical applications. Protective strategies, including encapsulation, anchoring, and three-dimensional substrate integration, can mitigate catalyst degradation and prolong operational lifespan.
Bridging theoretical modeling with experimental validation will be a key component to accelerating catalyst development. Machine learning-driven approaches offer a promising way to analyze large datasets, enabling the prediction and optimization of catalyst behavior. Moreover, integrating Ni-Se-based catalysts with photoelectrocatalysis presents exciting opportunities for visible light-assisted MOR, potentially improving energy efficiency [83]. The application of external driving fields, such as electric and magnetic fields, has also shown promise in enhancing catalytic activity and should be explored further [84,85,86,87,88].
Beyond catalytic performance, efficient separation and purification of formate from alkaline solutions remain a challenge. Scalable separation techniques, such as ion exchange resins and membrane-based processes, need to be developed for continuous and cost-effective production. Additionally, a detailed techno-economic analysis of catalyst synthesis, operational costs, and market viability will be crucial for commercialization.
Continuous efforts in Ni-based electrocatalysts, particularly in the application for MOR, hold significant promise for sustainable energy conversion and high-value chemical production. Addressing existing challenges while leveraging emerging opportunities will be key to unlocking the full potential of these catalysts in real-world applications. Given the broader impact of electrocatalysis, insights from this research could also be valuable for applications in waste-to-energy conversion and sustainable chemical manufacturing.

Author Contributions

Conceptualization, H.T., Y.Z. (Yan Zhong), Z.Y., C.Z. and Y.M.; methodology, H.G., Y.Z. (Yong Zhang) and N.J.; funding acquisition, H.T. and J.L.; writing—original draft preparation, H.T.; supervision, J.L.; writing—review and editing, J.L. All authors have read and agreed to the published version of the manuscript.

Funding

This work was funded by the National Natural Science Foundation of China (No. 12304276), the Central Guidance for Local Science and Technology Development Fund Projects (No. 2024ZYD0044), the Basalt Fiber and Composite Key Laboratory of Sichuan Province, Sichuan University of Arts and Science (XWFH-ZB-01 and XWFH-ZA-02), Scientific Research Foundation of Sichuan University of Arts and Sciences (No. 2023RC006Z), and the Research Institute of Intelligent Manufacturing Industry Technology of Sichuan Arts and Science University (grant no. ZNZZ2408).

Data Availability Statement

The authors confirm that the data supporting the findings of this study are available within the article. Raw data that support the findings of this study are available from the corresponding author upon reasonable request.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Manthiram, A.; Vadivel Murugan, A.; Sarkar, A.; Muraliganth, T. Nanostructured Electrode Materials for Electrochemical Energy Storage and Conversion. Energy Environ. Sci. 2008, 1, 621–638. [Google Scholar] [CrossRef]
  2. Turner, J.A. Sustainable Hydrogen Production. Science 2004, 305, 972–974. [Google Scholar] [CrossRef] [PubMed]
  3. Winsche, W.E.; Hoffman, K.C.; Salzano, F.J. Hydrogen: Its Future Role in the Nation’s Energy Economy. Science 1973, 180, 1325–1332. [Google Scholar] [CrossRef]
  4. Hao, Y.; Qiao, C.; Zhang, S.; Zhu, Y.; Ji, L.; Cao, C.; Zhang, J. Constructing Cation Vacancy Defects on NiFe-LDH Nanosheets for Efficient Oxygen Evolution Reaction. Energy Mater. Adv. 2023, 4, 0040. [Google Scholar] [CrossRef]
  5. Li, Y.; Wei, X.; Chen, L.; Shi, J. Electrocatalytic Hydrogen Production Trilogy. Angew. Chem. Int. Ed. 2020, 60, 19550–19571. [Google Scholar] [CrossRef]
  6. Quan, L.; Jiang, H.; Mei, G.; Sun, Y.; You, B. Bifunctional Electrocatalysts for Overall and Hybrid Water Splitting. Chem. Rev. 2024, 124, 3694–3812. [Google Scholar] [CrossRef]
  7. Huang, C.; Huang, Y.; Liu, C.; Yu, Y.; Zhang, B. Integrating Hydrogen Production with Aqueous Selective Semi-Dehydrogenation of Tetrahydroisoquinolines over a Ni2P Bifunctional Electrode. Angew. Chem. Int. Ed. 2019, 58, 12014–12017. [Google Scholar] [CrossRef] [PubMed]
  8. Sun, H.; Xu, X.; Chen, G.; Shao, Z. Perovskite Oxides as Electrocatalysts for Water Electrolysis: From Crystalline to Amorphous. Carbon Energy 2024, 6, e595. [Google Scholar] [CrossRef]
  9. Chen, F.Y.; Wu, Z.Y.; Adler, Z.; Wang, H. Stability Challenges of Electrocatalytic Oxygen Evolution Reaction: From Mechanistic Understanding to Reactor Design. Joule 2021, 5, 1704–1731. [Google Scholar] [CrossRef]
  10. Yan, Y.; Zhong, J.; Wang, R.; Yan, S.; Zou, Z. Trivalent Nickel-Catalyzing Electroconversion of Alcohols to Carboxylic Acids. J. Am. Chem. Soc. 2024, 146, 4814–4821. [Google Scholar] [CrossRef]
  11. Xia, Q.; Jin, C.; Huang, Y.L.; Zhai, Y.; Han, W.; Wu, J.; Xia, C.; Lin, C.C.; Zhao, X.; Zhang, X. Methanol-Facilitated Surface Reconstruction Catalysts for Near 200% Faradaic Efficiency in a Coupled System. Adv. Funct. Mater. 2024, 34, 2314596. [Google Scholar] [CrossRef]
  12. Meng, F.; Wu, Q.; Elouarzaki, K.; Luo, S.; Sun, Y.; Dai, C.; Xi, S.; Chen, Y.; Lin, X.; Fang, M.; et al. Essential Role of Lattice Oxygen in Methanol Electrochemical Refinery toward Formate. Sci. Adv. 2023, 9, eadh9487. [Google Scholar] [CrossRef]
  13. McCrory, C.C.L.; Jung, S.; Peters, J.C.; Jaramillo, T.F. Benchmarking Heterogeneous Electrocatalysts for the Oxygen Evolution Reaction. J. Am. Chem. Soc. 2013, 135, 16977–16987. [Google Scholar] [CrossRef] [PubMed]
  14. Zhou, Y.; Shen, X.; Wang, M.; Zhang, L.; Qian, T.; Yan, C.; Lu, J. The Understanding, Rational Design, and Application of High-Entropy Alloys as Excellent Electrocatalysts: A Review. Sci. China Mater. 2023, 66, 2527–2544. [Google Scholar] [CrossRef]
  15. Kahlstorf, T.; Hausmann, J.N.; Sontheimer, T.; Menezes, P.W. Challenges for Hybrid Water Electrolysis to Replace the Oxygen Evolution Reaction on an Industrial Scale. Glob. Chall. 2023, 7, 2200242. [Google Scholar] [CrossRef] [PubMed]
  16. Li, J.; Wei, R.; Wang, X.; Zuo, Y.; Han, X.; Arbiol, J.; Llorca, J.; Yang, Y.; Cabot, A.; Cui, C. Selective Methanol-to-Formate Electrocatalytic Conversion on Branched Nickel Carbide. Angew. Chemie 2020, 132, 21012–21016. [Google Scholar] [CrossRef]
  17. Li, J.; Li, L.; Ma, X.; Wang, J.; Zhao, J.; Zhang, Y.; He, R.; Yang, Y.; Cabot, A.; Zhu, Y. Unraveling the Role of Iron on Ni-Fe Alloy Nanoparticles during the Electrocatalytic Ethanol-to-Acetate Process. Nano Res. 2024, 17, 2328–2336. [Google Scholar] [CrossRef]
  18. Zhang, Y.; Liu, R.; Ma, Y.; Jian, N.; Pan, H.; Liu, Y.; Deng, J.; Li, L.; Shao, Q.; Li, C.; et al. Nickel-Cobalt Oxide Nanoparticles as Superior Electrocatalysts for Enhanced Coupling Hydrogen Evolution and Selective Ethanol Oxidation Reaction. J. Mater. Chem. A 2024, 12, 17252–17259. [Google Scholar] [CrossRef]
  19. Jian, N.; Ge, H.; Ma, Y.; Zhang, Y.; Li, L.; Liu, J.; Yu, J.; Li, C.; Li, J. Improved Methanol-to-Formate Electrocatalytic Reaction by Engineering of Nickel Hydroxide and Iron Oxyhydroxide Heterostructures. Sci. Energy Environ. 2025, 2, 3. [Google Scholar] [CrossRef]
  20. Ma, Y.; Ge, H.; Zhang, Y.; Jian, N.; Yu, J.; Arbiol, J.; Li, C.; Zhong, Y.; Li, L.; Kang, H.; et al. Selective Electrooxidation of Ethylene Glycol to Formate with Hydrogen Cogeneration in Ni3S2 Nanodomains on NiFeMn-LDH Nanosheet Arrays. ACS Sustain. Chem. Eng. 2025, 13, 5601–5612. [Google Scholar] [CrossRef]
  21. Liu, Y.P.; Zhao, S.F.; Guo, S.X.; Bond, A.M.; Zhang, J.; Zhu, G.; Hill, C.L.; Geletii, Y.V. Electrooxidation of Ethanol and Methanol Using the Molecular Catalyst [{Ru4O4(OH)2(H2O)4}(γ-SiW10O36)2]10−. J. Am. Chem. Soc. 2016, 138, 2617–2628. [Google Scholar] [CrossRef] [PubMed]
  22. Hu, Y.; Chao, T.; Dou, Y.; Xiong, Y.; Liu, X.; Wang, D. Isolated Metal Centers Activate Small Molecule Electrooxidation: Mechanisms and Applications. Adv. Mater. 2025, 37, 2418504. [Google Scholar] [CrossRef] [PubMed]
  23. Wang, Z.M.; Hong, Q.L.; Wang, X.H.; Huang, H.; Yu, C.; Li, S.N. Rup Nanoparticles Anchored on N-Doped Graphene Aerogels for Hydrazine Oxidation-Boosted Hydrogen Production. Wuli Huaxue Xuebao/Acta Phys. Chim. Sin. 2023, 39, 2303028. [Google Scholar] [CrossRef]
  24. Mao, Q.; Wang, W.; Deng, K.; Yu, H.; Wang, Z.; Xu, Y.; Li, X.; Wang, L.; Wang, H. Low-Content Pt-Triggered the Optimized d-Band Center of Rh Metallene for Energy-Saving Hydrogen Production Coupled with Hydrazine Degradation. J. Energy Chem. 2023, 85, 58–66. [Google Scholar] [CrossRef]
  25. Li, J.; Ma, Y.; Yu, J.; Li, L.; Yang, H.; Gu, W.; Shi, J.; Wang, J.; Zhu, Y. Enhanced Methanol Electrooxidation and Supercapacitive Performance via Compositional Engineering of Colloidal Ni-Co Alloying Nanoparticles. ChemSusChem 2024, 18, e202401098. [Google Scholar] [CrossRef] [PubMed]
  26. Xu, Y.; Liu, M.; Wang, M.; Ren, T.; Ren, K.; Wang, Z.; Li, X.; Wang, L.; Wang, H. Methanol Electroreforming Coupled to Green Hydrogen Production over Bifunctional NiIr-Based Metal-Organic Framework Nanosheet Arrays. Appl. Catal. B Environ. 2022, 300, 120753. [Google Scholar] [CrossRef]
  27. Sun, H.; Xu, X.; Fei, L.; Zhou, W.; Shao, Z. Electrochemical Oxidation of Small Molecules for Energy-Saving Hydrogen Production. Adv. Energy Mater. 2024, 14, 2401242. [Google Scholar] [CrossRef]
  28. Ghasemzadeh, K.; Sadati Tilebon, S.M.; Nasirinezhad, M.; Basile, A. Economic Assessment of Methanol Production. In Methanol: Science and Engineering; Elsevier: Amsterdam, The Netherlands, 2017; pp. 613–632. ISBN 9780444640109. [Google Scholar]
  29. Kishi, R.; Ogihara, H.; Yoshida-Hirahara, M.; Shibanuma, K.; Yamanaka, I.; Kurokawa, H. Green Synthesis of Methyl Formate via Electrolysis of Pure Methanol. ACS Sustain. Chem. Eng. 2020, 8, 11532–11540. [Google Scholar] [CrossRef]
  30. Ma, Y.; Li, L.; Zhang, Y.; Jian, N.; Pan, H.; Deng, J.; Li, J. Nickel Foam Supported Mn-Doped NiFe-LDH Nanosheet Arrays as Efficient Bifunctional Electrocatalysts for Methanol Oxidation and Hydrogen Evolution. J. Colloid Interface Sci. 2024, 663, 971–980. [Google Scholar] [CrossRef]
  31. Ma, Y.; Li, L.; Tang, J.; Hu, Z.; Zhang, Y.; Ge, H.; Jian, N.; Zhao, J.; Cabot, A.; Li, J. Electrochemical PET Recycling to Formate through Ethylene Glycol Oxidation on Ni-Co-S Nanosheet Arrays. J. Mater. Chem. A 2024, 12, 33917–33925. [Google Scholar] [CrossRef]
  32. Ullah, N.; Ullah, S.; Khan, S.; Guziejewski, D.; Mirceski, V. A Review: Metal-Organic Framework Based Electrocatalysts for Methanol Electro-Oxidation Reaction. Int. J. Hydrogen Energy 2023, 48, 3340–3354. [Google Scholar] [CrossRef]
  33. Majumdar, D.; Bhattacharya, S.K. Recent Developments of Methanol Electrooxidation Using Nickel-Based Nanocatalysts. ChemistrySelect 2022, 7, e202201807. [Google Scholar] [CrossRef]
  34. Chen, Z.; Han, N.; Zheng, R.; Ren, Z.; Wei, W.; Ni, B. Design of Earth-abundant Amorphous Transition Metal-based Catalysts for Electrooxidation of Small Molecules: Advances and Perspectives. SusMat 2023, 3, 290–319. [Google Scholar] [CrossRef]
  35. Zhao, L.; Zhu, Z.; Wang, J.; Zuo, J.; Chen, H.; Qi, X.; Niu, X.; Blackwood, D.J.; Chen, J.S.; Wu, R. Unlocking Proton Exchange Membrane Fuel Cell Performance with Porous PtCoV Alloy Catalysts. Adv. Mater. 2025, 2502457. [Google Scholar] [CrossRef]
  36. Liu, J.; Liu, H.; Wang, Q.; Li, T.; Yang, T.; Zhang, W.; Xu, H.; Li, H.; Qi, X.; Wang, Y.; et al. Phosphorus Doped PdMo Bimetallene as a Superior Bifunctional Fuel Cell Electrocatalyst. Chem. Eng. J. 2024, 486, 150258. [Google Scholar] [CrossRef]
  37. Liu, J.; Li, T.; Wang, Q.; Liu, H.; Wu, J.; Sui, Y.; Li, H.; Tang, P.; Wang, Y. Bifunctional PdMoPt Trimetallene Boosts Alcohol-Water Electrolysis. Chem. Sci. 2024, 15, 16660–16668. [Google Scholar] [CrossRef]
  38. Liu, H.; Li, T.; Wu, Z.; Xu, H.; Li, H.; Jing, R.; Wang, Y.; Liu, J. Integration of Phosphorus in PdCr Metallene for Enhanced CO-Tolerant Alcohol Electrooxidation. Inorg. Chem. 2024, 64, 123–132. [Google Scholar] [CrossRef]
  39. Kakati, N.; Maiti, J.; Lee, S.H.; Jee, S.H.; Viswanathan, B.; Yoon, Y.S. Anode Catalysts for Direct Methanol Fuel Cells in Acidic Media: Do We Have Any Alternative for Pt or Pt-Ru? Chem. Rev. 2014, 114, 12397–12429. [Google Scholar] [CrossRef]
  40. Liu, X.L.; Jiang, Y.C.; Huang, J.T.; Zhong, W.; He, B.; Jin, P.J.; Chen, Y. Bifunctional PdPt Bimetallenes for Formate Oxidation-Boosted Water Electrolysis. Carbon Energy 2023, 5, e367. [Google Scholar] [CrossRef]
  41. Cheng, H.; Wang, J.; Wu, C.; Liu, Z. Electrocatalysts for Formic Acid-Powered PEM Fuel Cells: Challenges and Prospects. Energy Mater. Adv. 2023, 4, 0067. [Google Scholar] [CrossRef]
  42. Swesi, A.T.; Masud, J.; Nath, M. Nickel Selenide as a High-Efficiency Catalyst for Oxygen Evolution Reaction. Energy Environ. Sci. 2016, 9, 1771–1782. [Google Scholar] [CrossRef]
  43. Yuan, B.; Luan, W.; Tu, S.T. One-Step Solvothermal Synthesis of Nickel Selenide Series: Composition and Morphology Control. CrystEngComm 2012, 14, 2145–2151. [Google Scholar] [CrossRef]
  44. Li, J.; Li, L.; Ma, X.; Han, X.; Xing, C.; Qi, X.; He, R.; Arbiol, J.; Pan, H.; Zhao, J.; et al. Selective Ethylene Glycol Oxidation to Formate on Nickel Selenide with Simultaneous Evolution of Hydrogen. Adv. Sci. 2023, 10, 2300841. [Google Scholar] [CrossRef]
  45. Anantharaj, S.; Noda, S. Nickel Selenides as Pre-Catalysts for Electrochemical Oxygen Evolution Reaction: A Review. Int. J. Hydrogen Energy 2020, 45, 15763–15784. [Google Scholar] [CrossRef]
  46. Xia, X.; Wang, L.; Sui, N.; Colvin, V.L.; Yu, W.W. Recent Progress in Transition Metal Selenide Electrocatalysts for Water Splitting. Nanoscale 2020, 12, 12249–12262. [Google Scholar] [CrossRef]
  47. Yang, C.; Lu, Y.; Duan, W.; Kong, Z.; Huang, Z.; Yang, T.; Zou, Y.; Chen, R.; Wang, S. Recent Progress and Prospective of Nickel Selenide-Based Electrocatalysts for Water Splitting. Energy Fuels 2021, 35, 14283–14303. [Google Scholar] [CrossRef]
  48. Li, J.; Yu, J.; Zhang, Y.; Li, C.; Ma, Y.; Ge, H.; Jian, N.; Li, L.; Zhang, C.Y.; Zhou, J.Y.; et al. Boosting Polysulfide Conversion on Fe-Doped Nickel Diselenide Toward Robust Lithium–Sulfur Batteries. Adv. Funct. Mater. 2025, 2501485. [Google Scholar] [CrossRef]
  49. Li, J.; Wang, X.; Xing, C.; Li, L.; Mu, S.; Han, X.; He, R.; Liang, Z.; Martinez, P.; Yi, Y.; et al. Electrochemical Reforming of Ethanol with Acetate Co-Production on Nickel Cobalt Selenide Nanoparticles. Chem. Eng. J. 2022, 440, 135817. [Google Scholar] [CrossRef]
  50. Wu, T.; Xu, Z.; Wang, X.; Luo, M.; Xia, Y.; Zhang, X.; Li, J.; Liu, J.; Wang, J.; Wang, H.L.; et al. Surface-Confined Self-Reconstruction to Sulfate-Terminated Ultrathin Layers on NiMo3S4 toward Biomass Molecule Electro-Oxidation. Appl. Catal. B Environ. 2023, 323, 122126. [Google Scholar] [CrossRef]
  51. Wang, X.; Ma, R.; Li, S.; Xu, M.; Liu, L.; Feng, Y.; Thomas, T.; Yang, M.; Wang, J. In Situ Electrochemical Oxyanion Steering of Water Oxidation Electrocatalysts for Optimized Activity and Stability. Adv. Energy Mater. 2023, 13, 2300765. [Google Scholar] [CrossRef]
  52. Li, S.; Liu, D.; Wang, G.; Ma, P.; Wang, X.; Wang, J.; Ma, R. Vertical 3D Nanostructures Boost Efficient Hydrogen Production Coupled with Glycerol Oxidation Under Alkaline Conditions. Nano-Micro Lett. 2023, 15, 189. [Google Scholar] [CrossRef]
  53. She, Z.W.; Kibsgaard, J.; Dickens, C.F.; Chorkendorff, I.; Nørskov, J.K.; Jaramillo, T.F. Combining Theory and Experiment in Electrocatalysis: Insights into Materials Design. Science 2017, 355, eaad4998. [Google Scholar] [CrossRef]
  54. Ren, J.; Zhang, Y.; Li, J.; Liu, J.; Hu, J.; Li, C.; Ke, Y.; Zhao, J.; Cabot, A.; Tang, B. Hydrothermal Nickel Selenides as Efficient Electrodes in Alkaline Media: Application to Supercapacitors and Methanol Oxidation Reaction. Dalt. Trans. 2024, 53, 18736–18744. [Google Scholar] [CrossRef]
  55. Ullah, N.; Guziejewski, D.; Mahmood, A.; Ullah, S.; Khan, S.; Hussain, S.; Imran, M. Three-Dimensionally Arranged NiSe2 Nanosheets as an Efficient Electrocatalyst for Methanol Electrooxidation Reaction. Energy Technol. 2024, 12, 2400390. [Google Scholar] [CrossRef]
  56. Jana, M.; Xu, R.; Cheng, X.B.; Yeon, J.S.; Park, J.M.; Huang, J.Q.; Zhang, Q.; Park, H.S. Rational Design of Two-Dimensional Nanomaterials for Lithium-Sulfur Batteries. Energy Environ. Sci. 2020, 13, 1049–1075. [Google Scholar] [CrossRef]
  57. Li, J.; Luo, Z.; He, F.; Zuo, Y.; Zhang, C.; Liu, J.; Du, R.; Yu, X.; Zhang, T.; Tang, P.; et al. Colloidal Ni-Co-Sn Nanoparticles as Efficient Electrocatalysts for the Methanol Oxidation Reaction. J. Mater. Chem. A 2018, 6, 22915–22924. [Google Scholar] [CrossRef]
  58. Dubale, A.A.; Zheng, Y.; Wang, H.; Hübner, R.; Li, Y.; Yang, J.; Zhang, J.; Sethi, N.K.; He, L.; Zheng, Z.; et al. High-Performance Bismuth-Doped Nickel Aerogel Electrocatalyst for the Methanol Oxidation Reaction. Angew. Chemie-Int. Ed. 2020, 59, 13891–13899. [Google Scholar] [CrossRef]
  59. Li, J.; Xing, C.; Zhang, Y.; Zhang, T.; Spadaro, M.C.; Wu, Q.; Yi, Y.; He, S.; Llorca, J.; Arbiol, J.; et al. Nickel Iron Diselenide for Highly Efficient and Selective Electrocatalytic Conversion of Methanol to Formate. Small 2021, 17, 2006623. [Google Scholar] [CrossRef]
  60. Ganguly, S.; Paul, S.; Khurana, D.; Khan, T.S.; Giri, P.K.; Loha, C.; Ghosh, S. Ternary Ni-Co-Se Nanostructure for Electrocatalytic Oxidative Value Addition of Biomass Platform Chemicals. ACS Appl. Energy Mater. 2023, 6, 5331–5341. [Google Scholar] [CrossRef]
  61. Meshesha, M.M.; Chanda, D.; Balu, R.; Jang, S.G.; Ahmed, S.; Yang, B.L. Efficient Green Hydrogen Production through Metal–Organic Framework-Derived Ni and Co Mediated Iron Selenide Hexagonal Nanorods and Wireless Coupled with Photovoltaics for Urea and Alkaline Water Electrolysis. Appl. Catal. B Environ. 2024, 344, 123635. [Google Scholar] [CrossRef]
  62. Li, S.; Ma, R.; Hu, J.; Li, Z.; Liu, L.; Wang, X.; Lu, Y.; Sterbinsky, G.E.; Liu, S.; Zheng, L.; et al. Coordination Environment Tuning of Nickel Sites by Oxyanions to Optimize Methanol Electro-Oxidation Activity. Nat. Commun. 2022, 13, 4679. [Google Scholar] [CrossRef]
  63. Zhang, Y.; Liu, R.; Ma, Y.; Jian, N.; Ge, H.; Pan, H.; Zhang, Y.; Zhang, C.; Liu, Y.; Deng, J.; et al. Surface Selenium Coating Promotes Selective Methanol-to-Formate Electrooxidation on Ni3Se4 Nanoparticles. Inorg. Chem. 2024, 63, 23328–23337. [Google Scholar] [CrossRef]
  64. Xin, Y.; Sun, L.; Huo, L.; Zhao, H. Co-Ni-P Nanoneedle Array Heterostructures with Built-In Potential for Selective Methanol Oxidation Coupled with H2 Evolution. ACS Appl. Nano Mater. 2023, 6, 10312–10321. [Google Scholar] [CrossRef]
  65. Wang, D.; Li, Y. Bimetallic Nanocrystals: Liquid-Phase Synthesis and Catalytic Applications. Adv. Mater. 2011, 23, 1044–1060. [Google Scholar] [CrossRef]
  66. Zhang, Q.; Jiang, Q.; Yang, X.; Zhang, C.; Zhang, J.; Yang, L.; He, H.; Ying, G.; Huang, H. Heterointerface Engineering of Rhombic Rh Nanosheets Confined on MXene for Efficient Methanol Oxidation. J. Energy Chem. 2024, 93, 419–428. [Google Scholar] [CrossRef]
  67. Liu, X.; Fang, Z.; Xiong, D.; Gong, S.; Niu, Y.; Chen, W.; Chen, Z. Upcycling PET in Parallel with Energy-Saving H2 Production via Bifunctional Nickel-Cobalt Nitride Nanosheets. Nano Res. 2023, 16, 4625–4633. [Google Scholar] [CrossRef]
  68. Peng, X.; Xie, S.; Wang, X.; Pi, C.; Liu, Z.; Gao, B.; Hu, L.; Xiao, W.; Chu, P.K. Energy-Saving Hydrogen Production by the Methanol Oxidation Reaction Coupled with the Hydrogen Evolution Reaction Co-Catalyzed by a Phase Separation Induced Heterostructure. J. Mater. Chem. A 2022, 10, 20761–20769. [Google Scholar] [CrossRef]
  69. Hu, L.; Zhong, P.; Zhu, J.; Wang, J.; Zheng, Y.; Zhang, Y.; Yang, H. Interfacial Engineering of Hydrangea-like MnSe/NiSe Heterostructure Catalysts for Methanol-Assisted Water Splitting. Mater. Lett. 2024, 377, 137417. [Google Scholar] [CrossRef]
  70. Du, J.; You, S.; Li, X.; Tang, B.; Jiang, B.; Yu, Y.; Cai, Z.; Ren, N.; Zou, J. In Situ Crystallization of Active NiOOH/CoOOH Heterostructures with Hydroxide Ion Adsorption Sites on Velutipes-like CoSe/NiSe Nanorods as Catalysts for Oxygen Evolution and Cocatalysts for Methanol Oxidation. ACS Appl. Mater. Interfaces 2020, 12, 686–697. [Google Scholar] [CrossRef]
  71. Hu, W.; Yan, Q.; Ma, S.; Gao, R.; Wang, Q.; Yuan, W. Surface-Selenization Formed NiFe MOF@NiSex Heterogeneous Arrays for Enhanced Oxygen Evolution and Methanol Electrooxidation. J. Electroanal. Chem. 2024, 975, 118789. [Google Scholar] [CrossRef]
  72. Zhao, B.; Liu, J.W.; Yin, Y.R.; Wu, D.; Luo, J.L.; Fu, X.Z. Carbon Nanofibers@NiSe Core/Sheath Nanostructures as Efficient Electrocatalysts for Integrating Highly Selective Methanol Conversion and Less-Energy Intensive Hydrogen Production. J. Mater. Chem. A 2019, 7, 25878–25886. [Google Scholar] [CrossRef]
  73. Gopalakrishnan, A.; Badhulika, S. Hierarchical Architectured Dahlia Flower-Like NiCo2O4/NiCoSe2 as a Bifunctional Electrode for High-Energy Supercapacitor and Methanol Fuel Cell Application. Energy Fuels 2021, 35, 9646–9659. [Google Scholar] [CrossRef]
  74. Jalali, F.; Sheikhi, S.; Hassani, N. Novel Selenide Composite as an Effective Bifunctional Electrocatalyst for Energy-Saving Hydrogen Production through Methanol-Assisted Water Electrolysis. Energy Fuels 2024, 39, 992–1004. [Google Scholar] [CrossRef]
  75. Shi, Y.; Li, H.; Ao, D.; Chang, Y.; Xu, A.; Jia, M.; Jia, J. 3D Nickel Diselenide Architecture on Nitrogen-Doped Carbon as a Highly Efficient Electrode for the Electrooxidation of Methanol and Urea. J. Alloys Compd. 2021, 885, 160919. [Google Scholar] [CrossRef]
  76. Cao, R.; Chang, Y.; Jia, J. CeO2-Ni2Co1Sex Catalysts Grown on N-Doped Carbon Substrates for Electrocatalytic Oxidation of Methanol and Urea. J. Alloys Compd. 2025, 1017, 179058. [Google Scholar] [CrossRef]
  77. Wang, X.; Wang, J.; Xu, A.; Chang, Y.; Jia, J.; Jia, M. Effect of in Situ Growth of NiSe2 on NiAl Layered Double Hydroxide on Its Electrocatalytic Properties for Methanol and Urea. Int. J. Hydrogen Energy 2023, 48, 22060–22068. [Google Scholar] [CrossRef]
  78. Zhao, B.; Liu, J.; Xu, C.; Feng, R.; Sui, P.; Wang, L.; Zhang, J.; Luo, J.L.; Fu, X.Z. Hollow NiSe Nanocrystals Heterogenized with Carbon Nanotubes for Efficient Electrocatalytic Methanol Upgrading to Boost Hydrogen Co-Production. Adv. Funct. Mater. 2021, 31, 2008812. [Google Scholar] [CrossRef]
  79. Luo, Q.; Peng, M.; Sun, X.; Asiri, A.M. In Situ Growth of Nickel Selenide Nanowire Arrays on Nickel Foil for Methanol Electro-Oxidation in Alkaline Media. RSC Adv. 2015, 5, 87051–87054. [Google Scholar] [CrossRef]
  80. Kavitha, M.; Alagarsamy, S.; Chen, S.M.; Muthuchudarkodi, R.R.; Shakina, J.; Tharmaraj, P. NiSe Integrated with Polymerized Reduced Carbon Sheet: As an Effective Electrocatalyst for Methanol Oxidation Reaction. Int. J. Hydrogen Energy 2024, 51, 1050–1059. [Google Scholar] [CrossRef]
  81. Jia, J.; Zhao, L.; Chang, Y.; Jia, M.; Wen, Z. Understanding the Growth of NiSe Nanoparticles on Reduced Graphene Oxide as Efficient Electrocatalysts for Methanol Oxidation Reaction. Ceram. Int. 2020, 46, 10023–10028. [Google Scholar] [CrossRef]
  82. Zhu, W.; Zhang, R.; Qu, F.; Asiri, A.M.; Sun, X. Design and Application of Foams for Electrocatalysis. ChemCatChem 2017, 9, 1721–1743. [Google Scholar] [CrossRef]
  83. Zhu, M.; Zhai, C.; Sun, M.; Hu, Y.; Yan, B.; Du, Y. Ultrathin Graphitic C3N4 Nanosheet as a Promising Visible-Light-Activated Support for Boosting Photoelectrocatalytic Methanol Oxidation. Appl. Catal. B Environ. 2017, 203, 108–115. [Google Scholar] [CrossRef]
  84. Zhang, C.Y.; Zhang, C.; Sun, G.W.; Pan, J.L.; Gong, L.; Sun, G.Z.; Biendicho, J.J.; Balcells, L.; Fan, X.L.; Morante, J.R.; et al. Spin Effect to Promote Reaction Kinetics and Overall Performance of Lithium-Sulfur Batteries under External Magnetic Field. Angew. Chemie-Int. Ed. 2022, 61, e202211570. [Google Scholar] [CrossRef] [PubMed]
  85. Yang, L.; He, R.; Botifoll, M.; Zhang, Y.; Ding, Y.; Di, C.; He, C.; Xu, Y.; Balcells, L.; Arbiol, J.; et al. Enhanced Oxygen Evolution and Zinc-Air Battery Performance via Electronic Spin Modulation in Heterostructured Catalysts. Adv. Mater. 2024, 36, 2400572. [Google Scholar] [CrossRef]
  86. Huang, Y.; Zhu, M.; Huang, Y.; Pei, Z.; Li, H.; Wang, Z.; Xue, Q.; Zhi, C. Multifunctional Energy Storage and Conversion Devices. Adv. Mater. 2016, 28, 8344–8364. [Google Scholar] [CrossRef]
  87. Liu, Z.; Tan, H.; Liu, D.; Liu, X.; Xin, J.; Xie, J.; Zhao, M.; Song, L.; Dai, L.; Liu, H. Promotion of Overall Water Splitting Activity Over a Wide PH Range by Interfacial Electrical Effects of Metallic NiCo-Nitrides Nanoparticle/NiCo2O4 Nanoflake/Graphite Fibers. Adv. Sci. 2019, 6, 1801829. [Google Scholar] [CrossRef]
  88. Zhao, Z.; Shen, X.; Luo, X.; Chen, M.; Zhang, M.; Yu, R.; Jin, R.; Zheng, H. Electric Field Redistribution Triggered Surface Adsorption and Mass Transfer to Boost Electrocatalytic Glycerol Upgrading Coupled with Hydrogen Evolution. Adv. Energy Mater. 2024, 14, 2400851. [Google Scholar] [CrossRef]
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Figure 1. (a) Schematic drawing of electrocatalytic HER coupled with OOR. (b) Different NORs and their carboxylic acid products. Reprinted from ref. [10]. Copyright 2024, American Chemical Society. (c) Radar plot of coupling way and traditional way. Reprinted from ref. [11]. Copyright 2024, Wiley-VCH GmbH. (d) Cumulative net profits of coupled MOR and HER. (e) Global warming effect for two electrolysis systems based on coupled MOR and HER versus electrocatalytic water splitting (OER and HER). Reprinted from ref. [12]. Copyright 2023, American Association for the Advancement of Science.
Figure 1. (a) Schematic drawing of electrocatalytic HER coupled with OOR. (b) Different NORs and their carboxylic acid products. Reprinted from ref. [10]. Copyright 2024, American Chemical Society. (c) Radar plot of coupling way and traditional way. Reprinted from ref. [11]. Copyright 2024, Wiley-VCH GmbH. (d) Cumulative net profits of coupled MOR and HER. (e) Global warming effect for two electrolysis systems based on coupled MOR and HER versus electrocatalytic water splitting (OER and HER). Reprinted from ref. [12]. Copyright 2023, American Association for the Advancement of Science.
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Figure 2. Common Ni-Se compounds and structures.
Figure 2. Common Ni-Se compounds and structures.
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Figure 3. (a) Schematic presentation of Ni-Se synthesis process. (b) CV curves of NiSe-, Ni3Se4-, and NiSe2-based electrodes in 1 M KOH with 1 M methanol, recorded within potential range of 0–0.7 V versus Hg/HgO. (c) Comparison of current density for these three electrodes in 1 M KOH with and without 1 M methanol at 0.5, 0.6, and 0.7 V versus Hg/HgO. (d) Long-term CA performance of Ni3Se4-based electrode at 0.6 V versus Hg/HgO over 20 h testing. (e) Corresponding IC profile of electrolyte at end of 20 h CA testing. (f) Optimization of methanol adsorption on NiSe(110), Ni3Se4(002), and NiSe2(111) surfaces. Reprinted from ref. [54]. Copyright 2024, The Royal Society of Chemistry.
Figure 3. (a) Schematic presentation of Ni-Se synthesis process. (b) CV curves of NiSe-, Ni3Se4-, and NiSe2-based electrodes in 1 M KOH with 1 M methanol, recorded within potential range of 0–0.7 V versus Hg/HgO. (c) Comparison of current density for these three electrodes in 1 M KOH with and without 1 M methanol at 0.5, 0.6, and 0.7 V versus Hg/HgO. (d) Long-term CA performance of Ni3Se4-based electrode at 0.6 V versus Hg/HgO over 20 h testing. (e) Corresponding IC profile of electrolyte at end of 20 h CA testing. (f) Optimization of methanol adsorption on NiSe(110), Ni3Se4(002), and NiSe2(111) surfaces. Reprinted from ref. [54]. Copyright 2024, The Royal Society of Chemistry.
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Figure 4. (a) Schematic representation of solution-based synthesis approach for Ni1−xFexSe2 nanorods. (b) CV curves recorded in 1 M KOH with 0.5 M methanol at 1.0–1.7 V vs. RHE with scan rate of 50 mV s−1. (c) Chronopotentiometry (CP) profile over 50,000 s at constant current density of 50 mA cm−2 and inset shows IC profile obtained from solution after CP testing. Reprinted from ref. [59]. Copyright 2021, Wiley-VCH GmbH. (d) XRD patterns of pure NiSe, CoSe, and various Ni1−xCoxSe structures. (e) HR-TEM image and corresponding structural analysis of Ni0.9Co0.1Se. (f) LSV plots comparing OER and MOR activities of different catalysts. (g) Comparison of OER and MOR activities of different catalysts at 1.65 V vs. RHE. (h) DFT optimized structures of Ni(OH)2, NiOOH, 1CoNi(OH)2, and 1CoNiOOH. (i) Optimized geometries of methanol adsorption and activation on Ni(OH)2(001) and 1CoNiOOH(001) surfaces. Color code: red for O, white for H, blue for Ni, and green for Co. Reprinted from ref. [60]. Copyright 2023, American Chemical Society.
Figure 4. (a) Schematic representation of solution-based synthesis approach for Ni1−xFexSe2 nanorods. (b) CV curves recorded in 1 M KOH with 0.5 M methanol at 1.0–1.7 V vs. RHE with scan rate of 50 mV s−1. (c) Chronopotentiometry (CP) profile over 50,000 s at constant current density of 50 mA cm−2 and inset shows IC profile obtained from solution after CP testing. Reprinted from ref. [59]. Copyright 2021, Wiley-VCH GmbH. (d) XRD patterns of pure NiSe, CoSe, and various Ni1−xCoxSe structures. (e) HR-TEM image and corresponding structural analysis of Ni0.9Co0.1Se. (f) LSV plots comparing OER and MOR activities of different catalysts. (g) Comparison of OER and MOR activities of different catalysts at 1.65 V vs. RHE. (h) DFT optimized structures of Ni(OH)2, NiOOH, 1CoNi(OH)2, and 1CoNiOOH. (i) Optimized geometries of methanol adsorption and activation on Ni(OH)2(001) and 1CoNiOOH(001) surfaces. Color code: red for O, white for H, blue for Ni, and green for Co. Reprinted from ref. [60]. Copyright 2023, American Chemical Society.
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Figure 5. (a) Schematic illustration of synthesis route for NiTx-R electrocatalysts through surface reconstruction. (b) Optimized structural models of oxyanion-doped NiOOH and pure NiOOH. (c) High-resolution Se 3d spectra of NiSex and NiSex-R. (d) Potential difference between MOR and OER at various current densities. (e) MOR polarization curves. Reprinted from ref. [62]. Copyright 2022, Creative Commons Attribution 4.0 International License. (f) CV curves of electrodes based on a-Se@NS-22.3%, a-Se@NS-17.3%, a-Se@NS-8.1%, and Ni3Se4 in 1 M KOH with 1 M methanol. (g) CA curves at 1.6 V over 18 h in methanol/alkaline solution for four electrodes. (h) Contact angle measurements of a-Se@NS-8.1%, Ni3Se4, and a-Se@NS-22.3% in electrolyte containing 1 M KOH and 1 M methanol, recorded at 500 ms intervals. (i) Developed DFT models of NiOOH and NiOOH-SeOx, along with corresponding Gibbs free energy landscape. Reprinted from ref. [63]. Copyright 2024, American Chemical Society.
Figure 5. (a) Schematic illustration of synthesis route for NiTx-R electrocatalysts through surface reconstruction. (b) Optimized structural models of oxyanion-doped NiOOH and pure NiOOH. (c) High-resolution Se 3d spectra of NiSex and NiSex-R. (d) Potential difference between MOR and OER at various current densities. (e) MOR polarization curves. Reprinted from ref. [62]. Copyright 2022, Creative Commons Attribution 4.0 International License. (f) CV curves of electrodes based on a-Se@NS-22.3%, a-Se@NS-17.3%, a-Se@NS-8.1%, and Ni3Se4 in 1 M KOH with 1 M methanol. (g) CA curves at 1.6 V over 18 h in methanol/alkaline solution for four electrodes. (h) Contact angle measurements of a-Se@NS-8.1%, Ni3Se4, and a-Se@NS-22.3% in electrolyte containing 1 M KOH and 1 M methanol, recorded at 500 ms intervals. (i) Developed DFT models of NiOOH and NiOOH-SeOx, along with corresponding Gibbs free energy landscape. Reprinted from ref. [63]. Copyright 2024, American Chemical Society.
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MDPI and ACS Style

Tu, H.; Zhong, Y.; Yang, Z.; Zhang, C.; Ma, Y.; Zhang, Y.; Jian, N.; Ge, H.; Li, J. Nickel Selenides in Electrocatalysis: Coupled Formate and Hydrogen Production Through Methanol Oxidation Reaction. Catalysts 2025, 15, 516. https://doi.org/10.3390/catal15060516

AMA Style

Tu H, Zhong Y, Yang Z, Zhang C, Ma Y, Zhang Y, Jian N, Ge H, Li J. Nickel Selenides in Electrocatalysis: Coupled Formate and Hydrogen Production Through Methanol Oxidation Reaction. Catalysts. 2025; 15(6):516. https://doi.org/10.3390/catal15060516

Chicago/Turabian Style

Tu, Hong, Yan Zhong, Zhihao Yang, Caihong Zhang, Yi Ma, Yong Zhang, Ning Jian, Huan Ge, and Junshan Li. 2025. "Nickel Selenides in Electrocatalysis: Coupled Formate and Hydrogen Production Through Methanol Oxidation Reaction" Catalysts 15, no. 6: 516. https://doi.org/10.3390/catal15060516

APA Style

Tu, H., Zhong, Y., Yang, Z., Zhang, C., Ma, Y., Zhang, Y., Jian, N., Ge, H., & Li, J. (2025). Nickel Selenides in Electrocatalysis: Coupled Formate and Hydrogen Production Through Methanol Oxidation Reaction. Catalysts, 15(6), 516. https://doi.org/10.3390/catal15060516

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