Search Results (286)

With the escalating challenges of global warming and the energy crisis, electrocatalytic CO₂ reduction reaction (CO₂RR) has emerged as a promising strategy to mitigate atmospheric CO₂ concentrations while converting it into high-value-added chemicals. Among various CO₂RR catalysts, copper-based materials exhibit unique capabilities for C-C coupling, yet their practical application remains constrained by several limitations: Low selectivity for C₂₊ products (typically <60%); Catalyst instability due to dynamic reconfiguration of active sites under high overpotentials; poor energy efficiency caused by competing hydrogen evolution reactions (HERs), etc. Recent studies demonstrate that nonmetallic heteroatom doping or functionalized ligand incorporation can effectively modulate the electronic structure and surface microenvironment of Cu-based catalysts, thereby enhancing CO₂RR performance. In this review, we comprehensively summarize recent advances in such strategies. We first systematically elucidate the unique advantages of copper-based catalysts as benchmark materials for multi-carbon (C₂₊) product synthesis, along with the current challenges they face. Subsequently, we highlight recent advances in modulating copper-based catalysts through the incorporation of diverse nonmetallic heteroatoms (e.g., N, S, B, P, halogens) or the introduction of functionalized ligands, with a particular focus on mechanistic insights and characterization methods aimed at enhancing C-C coupling efficiency and improving C₂₊ product selectivity. Finally, we present perspectives on the remaining opportunities and challenges in this research field. Full article

Electrochemical CO₂ reduction reaction through utilizing renewable electricity under mild conditions is a promising pathway toward achieving carbon neutrality. In this work, we designed a tubular graphyne functionalized with isolated Co single atom and lowered the activation energy barrier of its rate-determining step to as low as 0.46 eV. The catalytic performance was systematically evaluated through density functional theory calculations. Compared with the planar graphyne functionalized with isolated Co single atom, the tubular one not only significantly improves the utilization efficiency of Co single atoms by exposing them more thoroughly, but also increases the catalytic activity of Co single atom by enhancing electron density of states at the Fermi level, which causes a higher level of activation state for the adsorbed CO₂ molecules. Furthermore, it brought about the CO₂-to-CH₄ reduction reaction pathway, resulting in remarkable catalytic activity and high methane selectivity. Our study demonstrates the efficacy of curvature engineering in enhancing the intrinsic activity of single-atom catalysts, offering a novel strategy for designing advanced carbon cycle catalysts. Full article

Porphyrins are conjugated tetrapyrrolic macrocycles with tunable photophysical and catalytic properties, while covalent organic frameworks (COFs) are crystalline, porous polymers built from robust covalent linkages. Combining these motifs yields porphyrin-based COFs that couple ordered porosity with light-harvesting and metal-anchoring capabilities, offering promise for carbon dioxide capture and conversion. This review provides an integrated overview of their design, synthesis, structure, and function in the context of CO₂ capture, storage, and photocatalytic/electrocatalytic reduction. We survey recent literature, organize materials by linkage chemistry and topology, and summarize metallation, peripheral functionalization, and heterostructure strategies, compiling representative performance metrics where reported. The collected studies indicate that appropriate metallation and π-extension enhance light absorption and charge separation; high crystallinity and accessible pores facilitate mass transport; and electronic coupling to conductive phases improves catalytic activity and selectivity in CO₂ reduction. We close by outlining challenges and opportunities, including improving charge transport without sacrificing stability, pinpointing and quantifying active sites, and operando characterization to connect structure with function. This objective synthesis is intended to guide rational design of porphyrin-COFs for efficient and durable CO₂ management. Full article

This study reports the design of N- and S-doped ordered mesoporous carbon hollow spheres (OMCHS) as metal-free electrocatalysts for the oxygen reduction reaction (ORR) in alkaline media. Three electrocatalysts were synthesized using molecular precursors: (i) 2-thiophenemethanol (S-OMCHS), (ii) 2-pyridinecarboxaldehyde/2-thiophenemethanol (N1-S-OMCHS), and (iii) pyrrole/2-thiophenemethanol (N2-S-OMCHS). Among them, S-OMCHS exhibited the best activity (E_onset = 0.88 V, E_½ = 0.81 V, n ≈ 3.95), surpassing both co-doped analogs. After conducting an accelerated degradation test (ADT), S-OMCHS and N1-S-OMCHS showed improved catalytic behavior and outstanding long-term stability. Surface analysis confirmed that performance evolution correlates with heteroatom reorganization: S-OMCHS retained and regenerated thiophene-S and C=O/quinone species, while N1-S-OMCHS converted N-quaternary into N-pyridinic/pyrrolic, both enhancing O₂ adsorption and *OOH reduction through synergistic spin–charge coupling. Conversely, oxidation of N and loss of thiophene-S in N2-S-OMCHS led to partial deactivation. These results establish a direct link between surface chemistry evolution and electrocatalytic durability, demonstrating that controlled heteroatom doping stabilizes active sites and sustains the four-electron ORR pathway. The approach provides a rational design framework for next-generation, metal-free carbon electrocatalysts in alkaline fuel cells and energy conversion technologies. Full article

Nitrogen (N₂), constituting the majority of Earth’s atmosphere, remains indispensable for biological systems and underpins modern agriculture and industry. Traditionally, the Haber–Bosch process has been essential for synthesizing ammonia (NH₃) from N₂ under high temperature and pressure, but it contributes significantly to global CO₂ emissions. Recently, carbon-free electrocatalytic nitrogen reduction (e-NRR) has emerged as a promising, eco-friendly, and cost-effective approach for green NH₃ production under mild conditions using renewable energy, offering a sustainable alternative to the fossil fuel dependent Haber–Bosch process. This work explores NRR by contrasting the limitations of Haber–Bosch with the advantages of electrocatalysis. Despite progress, electrochemical N₂ reduction to NH₃ production remains challenging due to low activity, poor selectivity, stability, efficiency, and detection issues. Developing efficient e-NRR electrocatalysts is crucial to enhance activity, suppress hydrogen evolution reaction (HER), boost NH₃ yield, and improve Faradaic efficiency. This review highlights the role of layered double hydroxide (LDH) catalysts in e-NRR, summarizing the fundamental process, reaction pathways, and synthesis strategies. Ammonia detection methods, key metrics, and potential contamination issues are compared to inform standard NRR measurement protocols. Lastly, we summarize key findings to synthesize and improve LDH electrocatalysts for NH₃ production and a sustainable, carbon-free N₂ economy. Full article

The renewable-energy-powered electrocatalytic CO₂ reduction reaction (CO₂RR) efficiently converts CO₂ into high-value chemicals and fuels, offering a promising approach to addressing environmental and energy sustainability challenges. This process is of immense significance for constructing a sustainable artificial carbon cycle. Cu-based catalysts exhibit remarkable catalytic activity and broad product selectivity in CO₂RR, which can be attributed to their excellent electrical conductivity, moderate adsorption energy, and unique electronic structure. This review comprehensively summarizes the advantages, practical applications, and mechanistic insights of Cu-based catalysts in CO₂RR, with a systematic based on recent advances in tuning strategies via electronic effects and structural design. Specifically, it emphasizes the influence of electronic structure tuning (electron-donating/-withdrawing effects and steric hindrance effects), active center tuning (single-atom catalysts, heterogeneous synergetic effects, and polymer modification), and surface structure (morphology effect, valence-state effect, and crystalline-facet effect) influences on catalytic performance. By rationally designing the catalyst structure, the adsorption behavior of reaction intermediates can be effectively regulated, thereby enabling the highly selective generation of target products. The objective of this paper is to provide a theoretical framework and actionable strategies for the structural design and catalytic performance optimization of Cu-based catalysts, with the ultimate goal of promoting the development and practical application of efficient CO₂RR catalytic systems. Full article

Electrocatalytic conversion of CO₂ to high-energy-density multicarbon products (C₂₊) offers a sustainable route for renewable energy storage and carbon neutrality. Precisely modulating Cu-based catalysts to enhance C₂₊ selectivity remains challenging due to uncontrollable reduction of Cu^δ+ active sites. Here, an efficient and stable Ge/Cu catalyst was developed for CO₂ reduction to ethanol via Ge modification. A Cu₂O/GeO₂/Cu core–shell composite was constructed by controlling Ge doping. The structure–performance relationship was elucidated through in situ characterization and theoretical calculations. Ge⁴⁺ stabilized Cu¹⁺ active sites and regulated the surface microenvironment via electronic effects. Ge modification simultaneously altered CO intermediate adsorption to promote asymmetric CO–CHO coupling, optimized water structure at the electrode/electrolyte interface, and inhibited over-reduction of Cu^δ+. This multi-scale synergistic effect enabled a significant ethanol Faradaic efficiency enhancement (11–20%) over a wide potential range, demonstrating promising applicability for renewable energy conversion. This study provides a strategy for designing efficient ECR catalysts and offers mechanistic insights into interfacial engineering for C–C coupling in sustainable fuel production. Full article

Ammonia is an ideal candidate for clean energy in the future, and its large-scale production has long relied on the Haber–Bosch process, which operates at a high temperature and pressure. However, this process faces significant challenges due to the growing demand for ammonia and the increasing need for environmental protection. The high energy consumption and substantial CO₂ emissions associated with the Haber–Bosch method have greatly limited its application. Consequently, increasing research efforts have been devoted to developing green ammonia synthesis technologies. Among these, the electrocatalytic nitrogen reduction reaction (NRR), which uses water and nitrogen as raw materials to synthesize NH₃ under mild conditions, has emerged as a promising alternative. This method offers the potential for carbon neutrality and decentralized production when coupled with renewable electricity. However, it is important to note that the current energy efficiency and ammonia production rates of NRR under ambient aqueous conditions generally lag behind those of modern Haber–Bosch processes integrated with green hydrogen (H₂). As the core of the NRR process, the performance of electrocatalysts directly impacts the efficiency, energy consumption, and product selectivity of the entire reaction. To date, significant efforts have been made to identify the most suitable electrocatalysts. In this paper, we focus on the current research status of metal catalysts—including both precious and non-precious metals—as well as non-metal catalysts. We systematically review important advances in performance optimization, innovative design strategies, and mechanistic analyses of various catalysts. We clarify innovative optimization strategies for different catalysts and summarize and compare the catalytic effects of various catalyst types. Finally, we discuss the challenges facing electrocatalysis research and propose possible future development directions. Through this paper, we aim to provide guidance for the preparation of high-efficiency NRR catalysts and the future industrial application of electrochemical ammonia synthesis. Full article

This paper provides a systematic review of the latest advancements in metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) for electrocatalytic carbon dioxide reduction. Both materials exhibit high specific surface areas, tunable pore structures, and abundant active sites. MOFs enhance CO₂ conversion efficiency through improved conductivity, optimized stability, and selective regulation—including bimetallic synergy, pulse potential strategies, and tandem catalysis. COFs achieve efficient catalysis through precise design of single or multi-metal active sites, optimization of framework conjugation, and photo/electro-synergistic systems. Both types of materials demonstrate excellent selectivity toward high-value-added products (CO, formic acid, C₂⁺ hydrocarbons), but they still face challenges such as insufficient stability, short operational lifespan, high scaling-up costs, and poor electrolyte compatibility. Future research should integrate in situ characterization with machine learning to deepen mechanistic understanding and advance practical applications. Full article

Electrocatalytic CO₂ reduction driven by renewable electricity offers a sustainable approach to producing valuable chemicals, though it is often hindered by low activity and selectivity. CuO, an important transition metal oxide, exhibits unique advantages in photoelectrocatalysis due to its high intrinsic catalytic activity and ability to serve as an active site for CO₂ reduction. SiO₂, a widely used substrate, facilitates Cu loading and increases the specific surface area of the catalyst. Meanwhile, g-C₃N₄ provides excellent visible-light responsiveness and efficient charge carrier mobility. Together, CuO, SiO₂, and g-C₃N₄ are earth-abundant, low-cost, and chemically stable, making them ideal for solar-to-fuel applications. Here, a novel ternary heterojunction photocatalyst was constructed using SiO₂, CuO, and g-C₃N₄. The heterostructure significantly improves light-harvesting efficiency, promotes efficient charge separation and transport, and simultaneously mitigates photogenerated carrier recombination and catalyst corrosion. The resulting SiO₂@CuO/g-C₃N₄ catalyst demonstrates outstanding CO₂ conversion performance, achieving a CO yield of 17 mmolg⁻¹h⁻¹ at 1.2 V_RHE with nearly 100% selectivity. Moreover, this work systematically investigates the electrocatalytic CO₂ reduction reaction (CO₂RR) mechanism on Cu-based catalysts, offering insights into the formation of high-value multicarbon products and highlighting the potential of rational heterojunction design in enhancing solar-driven fuel production efficiency. Full article

Although Cu 3D structures are widely used in electrocatalytic practice, this electrode has not been studied enough in relation to the electrochemical transformation of CO₂ to C2 products. Cu foam samples were deposited from acidic solutions with varying concentrations of primary components (H₂SO₄, CuSO₄, and Cl⁻ ions) with the aim of determining the relationship between catalyst structure and activity/selectivity in producing C2 gaseous compounds during CO₂ electrochemical reduction. The deposited samples were characterized using SEM and electrochemical techniques, including Pb underpotential deposition (UPD), to determine the contribution of crystal facets. The most efficient electrodes were found to be those deposited in a solution without Cl⁻ additives. Their effectiveness was related to the shape and size of the crystallites forming the branches. These crystallites create a spatial structure that supports C-C coupling and C2 gaseous compound formation. The higher catalytic activity and selectivity of this electrode may also be related to its lower Cu(111) facet input to the overall facet distribution and its higher number of structural defects. Despite the higher electrochemically active surface area of samples deposited in the presence of Cl⁻ ions, their lower activity is related to structural characteristics that cause possible mass transfer limitations. Full article

The hierarchical porosity and active sites of porous carbon materials have significant impacts on the oxygen reduction reaction (ORR) process. The heteroatom-doped porous carbon materials (Z67-900, Z8-900, Z11-900, Z12-900) were synthesized by pyrolysis of ZIFs to reveal the synergistic effect of hierarchical porosity and Co-N_x sites. The structures of prepared materials were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectra, and nitrogen adsorption. The results of electrocatalytic performance show that Z67-900 has the best performance among the four materials prepared. The onset potential (E₀) of Z67-900 is close to commercial Pt/C (20%), and the half-wave potential (E_1/2) of Z67-900 is 80 mV positive than that of Pt/C in an O₂-saturated 0.1 M KOH solution (1600 rpm) with sweep rate of 5 mV·s⁻¹. Moreover, Z67-900 has better methanol resistance. The hierarchical pore structure of Z67-900 facilitates mass transfer, while the Co-N_x sites provide active catalytic centers. This study provides a solid foundation for the rational design of highly efficient ZIF-derived heteroatom-doped catalysts. Full article

The advancement of efficient energy conversion and storage technologies is fundamentally linked to the development of electrochemical systems, including fuel cells, batteries, and electrolyzers, whose performance depends on key electrocatalytic reactions: hydrogen evolution (HER), oxygen evolution (OER), oxygen reduction (ORR), carbon dioxide reduction (CO₂RR), and nitrogen reduction (NRR). Beyond catalyst design, the electrolyte microenvironment significantly influences these reactions by modulating charge transfer, intermediate stabilization, and mass transport, making electrolyte engineering a powerful tool for enhancing performance. This review provides a comprehensive analysis of how fundamental electrolyte properties, including pH, ionic strength, ion identity, and solvent structure, affect the mechanisms and kinetics of these five reactions. We examine in detail how the electrolyte composition and individual ion contributions impact reaction pathways, catalytic activity, and product selectivity. For HER and OER, we discuss the interplay between acidic and alkaline environments, the effects of specific ions, interfacial electric fields, and catalyst stability. In ORR, we highlight pH-dependent activity, selectivity, and the roles of cations and anions in steering 2e⁻ versus 4e⁻ pathways. The CO₂RR and NRR sections explore how the electrolyte composition, local pH, buffering capacity, and proton sources influence activity and the product distribution. We also address challenges in electrolyte optimization, such as managing competing reactions and maximizing Faradaic efficiency. By comparing the electrolyte’s effects across these reactions, this review identifies general trends and design guidelines for enhancing electrocatalytic performance and outlines key open questions and future research directions relevant to practical energy technologies. Full article

Single-atom catalysts supported by two-dimensional materials have been widely used in the electrochemical CO₂ reduction reaction (CO₂RR). Defects are inevitably generated during the preparation of two-dimensional materials. In this study, six Fe–N₄-doped graphene catalysts (CAT1–CAT6) containing single carbon vacancy defects were designed and calculated using density functional theory (DFT) calculations. The stability, catalytic activity and product selectivity of these catalysts for CO₂RR to C₁ products CO, HCOOH, CH₃OH and CH₄ were discussed and compared with the defect-free Fe−N₄-doped graphene catalyst (CAT0). The results show that CAT1–CAT6 all exhibit excellent thermodynamic and electrochemical stabilities. The possible reaction pathways for CO₂ reduction to different C₁ products were systematically investigated. The CAT2, CAT3 and CAT6 exhibit high selectivity for HCOOH, whereas the products of CAT1, CAT4 and CAT5 are HCOOH, CH₃OH and CH₄, the same as those of CAT0. Moreover, these six catalysts more effectively suppress the competing hydrogen evolution reaction (HER) compared to CAT0, indicating that the defect improves the catalytic selectivity of CO₂RR. Among all of the catalysts, CAT2 demonstrates the most prominent catalytic activity and selectivity toward the CO₂ reduction reaction (CO₂RR). The large distortion of Fe−N₄ in *HCOO with CAT2 contributes to the lower limiting potential U_L. We hope that the finding that the large distortion of Fe−N₄ could lower the limiting potential will provide theoretical insights for the design of more efficient CO₂RR electrocatalysts. Full article

Because the interfacial Cu⁰/Cu⁺ in Cu-based electrocatalyst promotes CO₂ electroreduction activity, it would be highly desirable to physically separate Cu-based nanoparticles through coating shells and load them onto porous carriers. Herein, multilayered graphene-coated Cu (Cu@G) nanoparticles with tailorable core diameters (28.2–24.2 nm) and shell thicknesses (7.8–3.0 layers) were fabricated via lased ablation in liquid. A thin Cu₂O layer was confirmed between the interface of the Cu core and the graphene shell, providing an interfacial Cu⁰/Cu⁺. Cu@G cross-linked biochars (Cu@G/Bs) with developed porosity (31.8–155.9 m²/g) were synthesized. Morphology, crystalline structure, porosity, and elemental chemical states of Cu@G and Cu@G/Bs were characterized. Cu@G/Bs captured CO₂ with a maximum sorption capacity of 107.03 mg/g at 0 °C. Furthermore, 95.3–97.1% capture capacity remained after 10 cycles. Cu@G/Bs exhibited the most superior performance with 40.7% of FE_C2H4 and 21.7 mA/cm² of current density at −1.08 V vs. RHE, which was 1.7 and 2.7 times higher than Cu@G. Synergistic integration of developed porosity for efficient CO₂ capture and the fast charge transfer rate of interfacial Cu₂O/Cu enabled this improvement. Favorable long-term stability of the phase/structure and CO₂ electroreduction activity were present. This work provides new insight for integrating Cu@G and a biochar platform to efficiently capture and electro-reduce CO₂. Full article