Search Results (986)

Functional materials based on LaCoSi and LaCuSi intermetallic compounds (IMC) were fabricated and tested in the electrocatalytic process of reducing nitrates to ammonia (NO₃RR). The method of arc melting in an argon atmosphere was used to synthesize the alloys. The synthesis process is described and analyzed in detail, and the difficulties and advantages are shown. It has been established that when using an LaCuSi-based IMC–alloy as an electrocatalyst, the reduction of nitrates is the predominant reaction. On the contrary, for the LaCoSi (IMC)–alloy electrocatalyst, NO₃RR and the hydrogen evolution reaction (HER) occur simultaneously. Full article

The acquisition of liquid energy sources and basic chemicals from washing water via Kolbe electrolysis is of great significance for achieving the goal of carbon-neutrality. However, oleophilic products tend to adhere to the platinum (Pt) electrode, which results in a shortened working life for Kolbe electrolysis. To address these issues, a novel method for endowing carbon fiber paper electrodes with underwater superoleophobic properties through simple electrodeposition is reported herein. The underwater superoleophobic electrodes improve the efficiency of the Kolbe electrolysis reaction, as oleophilic products can be easily removed from the electrode surface, thereby exposing more active reaction sites. Importantly, the underwater superoleophobic electrodes have fully demonstrated their capability of excellent electrochemical performance, stability, and durability. This work provides a novel approach for the design of high-performance electrodes in organic electro-catalysis. Full article

The nickel-derived metal–organic framework (MOF), Ni-BTB, synthesized from 4,4′,4″-benzene-1,3,5-tribenzoic acid (H₃BTB), was investigated as a multifunctional platform for enhanced energy applications including production and storage. In catalytic hydrogen generation by NaBH₄ hydrolysis, Ni-BTB attained a hydrogen generation rate (HGR) of 4640 mL H₂/g•min with 1 mg of catalyst, with an activation energy of 76.44 kJ/mol. Under optimized reaction conditions (60 °C, 20 mg catalyst, and 1 g NaBH₄), the HGR increased to 9542 mL H₂/g•min, while exhibiting high recyclability throughout four successive cycles. As a supercapacitor electrode, Ni-BTB achieved a specific capacitance of 156 F/g at 1 A/g and showed remarkable cycling stability, maintaining its capacitance after 10,000 charge–discharge cycles. Furthermore, Ni-BTB exhibited exceptional electrocatalytic activity for oxygen evolution reaction (OER), requiring only 106 mV overpotential to achieve 10 mA/cm², offering a time-of-flight (TOF) of 0.0585 s⁻¹ and demonstrating significant operational longevity of at least 12 h. These findings underscore Ni-BTB as a durable, reusable, and adaptable material for hydrogen production, energy storage, and electrocatalytic applications. Full article

Catalytic materials are central to the advancement of hydrogen generation technologies, playing a pivotal role in enabling sustainable, carbon-neutral energy systems. Hydrogen can be produced via electrochemical water splitting, thermochemical reforming, or photocatalysis—each imposing unique performance requirements on catalysts in terms of activity, selectivity, stability, and efficiency. While traditional noble metals (e.g., platinum, ruthenium, iridium) provide benchmark catalytic activity, their widespread use is hindered by scarcity, high cost, and limited long-term durability. Consequently, researchers have increasingly focused on earth-abundant alternatives such as transition metals (Ni, Co, Fe, Mo), alloys, metal oxides, carbides, sulfides, nitrides, and carbon-based systems. Among these, two-dimensional materials, particularly the MXene family, have attracted significant attention due to their metallic conductivity, layered structure, and tunable surface chemistry. These features enable rapid charge transfer and abundant active sites, making MXenes and related nanostructured catalysts promising for both the Hydrogen Evolution Reaction (HER) and Oxygen Evolution Reaction (OER) across a wide range of electrochemical conditions. Parallel efforts have integrated novel semiconductors, plasmonic nanomaterials, and hybrid heterostructures to improve the efficiency of solar-to-hydrogen energy conversion. This paper reviews the main types of catalytic materials used in hydrogen production, explains their design strategies and structure–performance relationships, and discusses key engineering challenges such as integrating renewable energy sources, scaling up manufacturing, and ensuring long-term durability in real-world systems. Future research goals are also highlighted, including the development of affordable non-noble catalysts, enhancing catalyst stability through surface and defect engineering, and coupling hydrogen production with circular economy principles, all of which are essential to making hydrogen generation more efficient, scalable, and cost-effective as the world transitions to clean and sustainable energy. Full article

Pt-based catalysts remain the most effective materials for the oxygen reduction reaction (ORR) at the cathode of proton exchange membrane fuel cells (PEMFCs); however, platinum scarcity and high cost severely limit the large-scale deployment of the technology. Improving catalytic activity and durability through precise control of nanoparticle morphology is therefore crucial for reducing costs and enhancing sustainability, enabling PEMFC widespread adoption. In this context, carbon-supported Pt-based nanoparticles with a 30 wt.% Pt loading were synthesized by an organometallic chemistry approach using hexadecylamine (HDA) as a stabilizer, allowing fine control over nanoparticle morphology. Two distinct synthesis pathways (one-pot and two-step procedures) were used to prepare platinum catalysts supported on KetjenBlack EC-300J (KB), and their influence on the electrocatalytic activity of the obtained nanomaterials was studied. Furthermore, the effect of HDA stabilization on catalyst performance was investigated. Directly synthesized Pt/KB catalysts exhibited similar ORR mass activity, regardless of whether or not HDA was present. Pt/KB prepared by the two-step procedure showed a significantly lower performance. Additionally, despite a larger loss of electrochemical surface area during an accelerated stress test compared to a commercial Pt/C reference, Pt^HDA/KB and Pt/KB catalysts maintained stable mass activity and limited specific activity degradation, highlighting the beneficial effect of nanoparticle stabilization in the presence of HDA on prolonged electrocatalyst cycling. Full article

The electrochemical reduction of CO₂ offers a sustainable approach to transforming carbon dioxide into value-added products when powered by renewable energy. However, current electrocatalysts lack efficiency and selectivity, hindering commercial application. Combining tin’s high formate selectivity with copper’s ability to reduce CO₂ via COOH* pathway offers a promising strategy. This synergy mitigates copper’s low selectivity, providing a cost-effective catalyst with enhanced performance over pure Sn-based systems. This work investigates CuSn bimetallic electrocatalysts synthesised by scalable electrodeposition onto gas diffusion layers to boost formate production. Catalytic performance and cell potential were evaluated at current densities ranging from 50 to 200 mA cm⁻² and varying Sn compositions. Catalysts with Sn content below 4% predominantly formed CO and H₂, but smaller particles and improved metal dispersion increased formate production. A catalyst containing 12% Sn achieved a maximum faradaic efficiency (FE) of 52% at 50 mA cm⁻² with an iR-corrected potential of −0.56 V vs. SHE. At 200 mA cm⁻², it exhibited a 30% FE for formate, along with 31% FE for CO and 9.3% FE for H₂, while other gases contributed to less than 4% FE, indicating potential as syngas feedstock. Higher Sn content, combined with smaller, well-distributed particles, effectively suppressed H₂, CO, and other by-products, highlighting a strong dependence of FE on Sn content and bimetallic distribution, demonstrating compositional tuning importance via electrodeposition. Full article

Hollow nanostructures have emerged as a pivotal class of nanomaterials in electrocatalysis, offering intrinsic advantages such as high surface-to-volume ratios, reduced density, and economical utilization of precious metals. However, the prevailing research paradigm has predominantly focused on the external shell characteristics while overlooking the decisive role of the interior cavity microenvironment. This review introduces a novel conceptual framework that positions the rational engineering of the cavity microenvironment—encompassing mass transport dynamics, localized electronic structure modulation, active site exposure, and structural stability—as a unified design principle for next-generation electrocatalysts. We systematically elucidate how precise control over cavity geometry, composition, and interfacial properties can optimize electrocatalytic performance for oxygen reduction (ORR), oxygen evolution (OER), and hydrogen evolution (HER) reactions. By correlating microenvironmental parameters with catalytic metrics, we establish structure–property–performance relationships and highlight recent breakthroughs. Finally, we outline future challenges in achieving atomic-level precision in cavity design, understanding dynamic evolution under operating conditions, and scaling up synthesis for industrial applications. Full article

The water–energy–carbon (WEC) nexus provides a systems framework for minimizing trade-offs among water security, energy reliability, and carbon mitigation. Within this framework, waste-derived biochar catalysts offer a circular pathway that simultaneously valorizes residues, reduces process energy demand, and supports carbon management through stable carbon storage and catalytic co-benefits. This review consolidates recent advances in biochar-based catalysts engineered from agricultural, industrial, municipal, and sludge-derived wastes, highlighting how feedstock selection and thermochemical processing, namely pyrolysis, hydrothermal carbonization (HTC), and torrefaction, as well as activation and post-modification (heteroatom doping and metal/metal-oxide incorporation) govern structure–property–performance relationships. The synthesized catalysts have been widely applied in water and wastewater treatment, including adsorption–advanced oxidation process (AOP) hybrids, Fenton-like systems, peroxydisulfate/persulfate (PS) and peroxymonosulfate (PMS) activation, photocatalysis, and the removal of emerging contaminants. They have also demonstrated strong potential in energy conversion processes such as the hydrogen evolution reaction (HER), oxygen reduction and evolution reactions (ORR/OER), biomass reforming, and carbon dioxide (CO₂) conversion. In addition, these materials contribute to carbon management through sequestration pathways, avoided emissions, and life cycle assessment (LCA)-based sustainability evaluations. Finally, we propose a WEC-aligned design roadmap integrating techno-economic analysis (TEA), LCA, and scale-up considerations to guide next-generation biochar catalysts toward robust performance in real matrices and deployment-ready systems. Full article

Water electrolysis is a key technology for sustainable hydrogen production and a cornerstone of future low-carbon energy systems. However, large-scale deployment is constrained not only by efficiency and cost, but increasingly by the sustainability and availability of materials used in electrocatalysts and membranes. This review provides a materials-centric assessment of state-of-the-art and emerging electrocatalysts for alkaline (AEL), proton exchange membrane (PEM), and solid oxide electrolysis (SOEC) technologies, emphasizing the interdependence of performance, durability, cost, and sustainability. Electrocatalyst activity and stability are linked to cell- and stack-level efficiency, energy demand, and the levelized cost of hydrogen. Life cycle assessment (LCA) and resource criticality analyses are integrated to quantify environmental impacts, supply risks, and recycling potential of key materials, including platinum group metals, nickel, rare earth elements, and ceramic oxides. Particular attention is given to recycling and circularity strategies, which are essential for mitigating material scarcity and reducing upstream emissions, especially in PEM electrolyzers. Emerging catalyst concepts such as single-atom catalysts, high-entropy alloys, and noble-metal-free systems are discussed as promising pathways to reduce critical material dependence. The review concludes by highlighting the need for integrated material–technology–system approaches to enable efficient, scalable, and truly sustainable hydrogen production. Full article

To facilitate the next generation of renewable energy devices, it is important to engineer oxygen reduction reaction (ORR) catalysts that balance efficiency and production costs. This work examines oxygen adsorption on the WC (0001) surface as a function of electrode potential, utilizing DFT simulations with an implicit solvent environment. The results demonstrate that electrode potential significantly influences oxygen adsorption energy and electronic structure. Among the adsorption sites examined, the top site exhibits the highest stability across the entire potential range. The observed reduction in adsorption energy at lower potentials is attributed to the d-band center moving further from the Fermi energy, which weakens C–O orbital interactions, as revealed by DOS and COHP analyses. Our results demonstrate the crucial role of electrochemical conditions in modulating catalytic behavior and provide valuable insights for optimizing tungsten carbide (WC)-based electrocatalysts for ORR applications. Full article

In this study, FeCoNiMoCu high-entropy alloy thin films were sulfided at different temperatures ranged from 250 °C to 450 °C by chemical vapor deposition, and the resultant sulfided Fe-Co-Ni-Mo-Cu-S alloys were characterized by means of XRD, SEM, XPS and EDS. HER performance tests were carried out in four electrolyte systems, namely 0.5 M H₂SO₄, 1 M KOH, 1 M KOH + 0.5 M NaCl and 1 M KOH + 1 M Na₂S. The results indicated that the as-prepared electrodes exhibited low HER overpotentials in all four electrolytes, with the optimal catalytic performance consistently achieved at a sulfidation temperature of 350 °C. Among the tested systems, the electrode delivered the best HER activity in 0.5 M H₂SO₄, showing an overpotential of merely 53 mV and a Tafel slope of 86.72 mV dec⁻¹ at a current density of 10 mA·cm⁻². In 1.0 M KOH, the overpotential required to reach the same current density was 98 mV with a Tafel slope of 72.43 mV dec⁻¹. For the mixed electrolyte of 1 M KOH and 0.5 M NaCl, the overpotential at 10 mA·cm⁻² was 142 mV accompanied by a Tafel slope of 49.51 mV dec⁻¹. In contrast, the 1 M KOH + 1 M Na₂S electrolyte yielded an overpotential of 77 mV and a Tafel slope of 84.01 mV dec⁻¹ at the identical current density. HER tests revealed that the sulfidation temperature exerts a significant influence on the formation and distribution of active phases of multi-metal sulfides (e.g., FeS_x, CoS_x, NiS_x, MoS₂) on the electrode surface. The electrodes prepared at an appropriate sulfidation temperature exhibit a larger specific surface area and enhanced hydrogen evolution reaction performance for water electrolysis. These findings may provide useful references for other researchers in the design and fabrication of high-entropy alloy-based HER catalysts. Full article

CoNi layered double hydroxides (CoNiLDHs) were successfully synthesized on nickel foam (NF) using a hydrothermal method. X-ray diffraction (XRD) analysis confirmed the formation of a well-defined hydrotalcite-like phase, including a strong (003) peak, indicating layered stacking. Scanning electron microscopy (SEM) revealed a 3D hierarchical nanosheet structure resembling flower-like arrays, which was further supported by EDS mapping showing a uniform distribution of Co, Ni, and O. Electrochemical studies demonstrated excellent OER activity, with a low overpotential of 188 mV at 10 mA/cm² and a Tafel slope of 97.48 mV/dec, inferring rapid reaction kinetics. Furthermore, the material exhibited a significant electrochemical surface area (ECSA) compared to bare NF. Chronoamperometry over 24 h confirmed the operational durability catalyst, stabilizing around 7–8 mA/cm², validating its potential as a cost-effective and efficient OER electrocatalyst in alkaline media. Full article

Ethylene glycol oxidation reaction (EGOR) is a promising anodic process to reduce the cell voltage compared with the oxygen evolution reaction (OER). Using ethylene glycol (EG) obtained from biomass-derived streams—such as cellulose, hemicellulose or lignocellulosic intermediates—and polyethylene terephthalate (PET) waste contributes to the development of circular-economy models. This study investigates EGOR on a non-noble NiCo bimetallic electrode, focusing on the effects of temperature and current density. The presence of EG reduces the initial potential by 240 mV at 25 °C, with a further 60 mV decrease at elevated temperatures, while the catalyst maintains high formate selectivity (>65%) across the tested conditions. Faradaic efficiency peaks at 100 mA cm⁻² due to the full oxidation of formate to CO₂ or the competing OER at higher current densities. There are no significant discrepancies between simulated and experimental faradaic efficiencies, although the presence of terephthalic acid (TPA) affects the shift in the electrode potential. Overall, these results highlight the relevance of EGOR for future applications in which EG derived from recycled plastics and renewable biomass can be electrochemically valorized within integrated biorefinery frameworks. Full article

Magnetic-field-assisted electrocatalysis offers a powerful route to enhance the oxygen evolution reaction (OER) by coupling spin-dependent effects with magnetohydrodynamic phenomena. Here, we present a unified study of cobalt ferrite (CoFe₂O₄)-based nanofilms, elucidating the combined roles of rare-earth doping, nanoparticle size, film morphology, and electrode substrate magnetism on OER performance under external magnetic fields. The effect of UV-light irradiation is also investigated. CoFe₂O₄ and yttrium-doped CoFe₂O₄ nanoparticles were synthesized via thermal decomposition and self-combustion routes, yielding single-domain particles with distinct structural and magnetic properties, and assembled into homogeneous nanofilms using the Langmuir–Blodgett technique. Electrocatalytic measurements in alkaline media reveal that intrinsic OER activity is primarily governed by film compactness and charge-transfer efficiency, while the magnitude of magnetic-field-induced enhancement depends on the magnetic response of both the nanofilms and the supporting electrode. Ferromagnetic substrates promote enhanced catalytic activity under magnetic fields, whereas diamagnetic substrates can exhibit suppressed performance. Across all systems, the strongest enhancement is observed when the magnetic field is applied parallel to the electrode surface, reflecting the combined effects of spin polarization and Lorentz-force-driven mass transport. UV-light irradiation is also evaluated as an external stimulus to promote the reaction. Our findings establish a comprehensive framework for designing magnetically assisted OER electrocatalysts and demonstrate that magnetic-field effects can rival or complement rare-earth doping or UV-light irradiation, offering a sustainable pathway toward high-efficiency water oxidation. Full article

Modified electrodes were obtained by immobilizing Mn³⁺ complexes with the following tetraazamacrocycles (1,4,7,10-tetraazacyclododecane ([12]aneN₄), 1,4,8,11-tetrazacyclotetradecane ([14]aneN₄), 1,4,7,11-tetrazacyclotetradecane (iso[14]aneN₄), and 1,4,8,12-tetrazacyclopentadecane ([15]aneN₄) in a Nafion film on the surface of a glassy carbon electrode (GCE). Based on spectroelectrochemical, chronopotentiometric, and chronoamperometric studies, oxidation of mononuclear complexes to dinuclear di-μ-oxo complexes of Mn³⁺ and Mn⁴⁺ was observed, and the mechanism and influence of Nafion on this process were determined. On the basis of voltammetric and chronocoulometric studies, the electroactivity, stability, and diffusion rates of such modified electrodes were demonstrated. Based on voltammetric and chronocoulometric studies, their electrocatalytic properties were analyzed in relation to the oxidation of model compounds used in this type of research, namely, ascorbic acid, glycolaldehyde, and glycolic acid. Full article