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Protonic ceramic fuel cells (PCFCs), which are based on proton conducting electrolytes, are a class of power generation devices that can efficiently operate at the intermediate (500–700 °C), even low (450 °C) temperatures, but their development is hindered by sluggish cathodic kinetics at reduced temperatures. At the PCFC cathode, the absorbed oxygen molecules react with oxygen vacancies, protons and electrons to generate water and release electrical energy. Thus, the PCFC cathode materials require percolation network for proton, oxide-ion, and electron carriers simultaneously. In this work, we developed a triple ionic-electronic conductor BaCo 0.4 Fe 0.4 Zr 0.15 W 0.05 O 3-δ as a new cathode material for the PCFCs using BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ as the electrolyte. Anode supported cells were fabricated and the performances were investigated. Compared with the parent oxide, tungsten doping can significantly improve the electrochemical reduction kinetic of oxygen. The BaCo 0.4 Fe 0.4 Zr 0.15 W 0.05 O 3-δ based PCFC obtained the peak power density of 688 mW ⋅ cm−2 at 600 °C, which is 1.29 time higher than that of BaCo 0.4 Fe 0.4 Zr 0.2 O 3-δ based PCFC (the peak power density of 534 mW ⋅ cm−2 at 600 °C). Moreover, BaCo 0.4 Fe 0.4 Zr 0.15 W 0.05 O 3-δ has a better thermal expansion matching with the electrolyte material BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] Electrochemical nitrate reduction reaction (NO 3 RR) offers a cost-effective and environmentally friendly method to simultaneously yield valuable NH 3 and alleviate NO 3 − pollution under mild operating conditions. However, this complicated eight-electron reaction suffers from low selectivity and Faradaic efficiency, which highlight the importance of developing efficient catalysts, but still a critical challenge. Here, a theoretical screening is performed on transition metal-tetragonal carbon nitride (TM@T-C 2 N) as active and selective electrocatalysts for NO 3 RR, where detailed reaction mechanisms and activity origins are explored. In addition, five-step screening criteria and volcano plots enable fast prescreening among numerous candidates. We identify that V@T-C 2 N and Cr@T-C 2 N are promising candidates with low overpotentials and high selectivity and stability. In particular, a significant negative correlation between the adsorption strength of nitrate and the Gibbs free energy for the last proton-electron coupling step (*NH 2 →*NH 3) was existed, which is considerably advantaged to track the activity trend and reveal the origin of activity. This work provides theoretical insights into the rational design of TM–N 4 /C catalysts for NO 3 RR and paves a valuable electrochemical screening framework for other multi-step reactions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Atomically dispersed catalyst with single Cu atom and atomic Ni clusters was prepared. • Cu SA Ni AC /NMHCS achieves a high FE CO of over 90% across a wide potential range. • Cu SA Ni AC /NMHCS shows the highest FE CO of 98 % at − 0.9 V vs. RHE. • Cu SA Ni AC /NMHCS exhibits excellent long-term stability for CO 2 RR to produce CO. • Positively shifted ε d of Ni 3 d orbital contributes to the enhanced CO 2 RR performance. The rational design of catalysts with atomic dispersion and a deep understanding of the catalytic mechanism is crucial for achieving high performance in CO 2 reduction reaction (CO 2 RR). Herein, we present an atomically dispersed electrocatalyst with single Cu atom and atomic Ni clusters supported on N-doped mesoporous hollow carbon sphere (Cu SA Ni AC /NMHCS) for highly efficient CO 2 RR. Cu SA Ni AC /NMHCS demonstrates a remarkable CO Faradaic efficiency (FE CO) exceeding 90% across a potential range of −0.6 to −1.2 V vs. reversible hydrogen electrode (RHE) and achieves its peak FE CO of 98% at −0.9 V vs. RHE. Theoretical studies reveal that the electron redistribution and modulated electronic structure—notably the positive shift in d-band center of Ni 3 d orbital—resulting from the combination of single Cu atom and atomic Ni clusters markedly enhance the CO 2 adsorption, facilitate the formation of *COOH intermediate, and thus promote the CO production activity. This study offers fresh perspectives on fabricating atomically dispersed catalysts with superior CO 2 RR performance. [ABSTRACT FROM AUTHOR]

Electrochemical conversion of waste nitrate (NO3−) to ammonia (NH3) for environmental applications, such as carbon‐neutral energy sources and hydrogen carriers, is a promising alternative to the energy‐intensive Haber–Bosch process. However, increasing the energy efficiency is limited by the high overpotential and selectivity. Herein, a Co─Cu mixed single‐atom/cluster catalyst (Co─Cu SCC) is demonstrated—with well‐dispersed Co and Cu active sites anchored on a carbon support—that delivers high NH3 Faradaic efficiency of 91.2% at low potential (–0.3 V vs. RHE) due to synergism between the heterogenous active sites. Electrochemical analyses reveal that Cu in Co─Cu SCC preferentially catalyzes the NO3−‐to‐NO2− pathway, whereupon Co catalyzes the NO2−‐to‐NH3 pathway. This tandem electroreduction bypasses the rate‐determining steps (RDSs) for Co and Cu to lower the reaction energy barrier and surpass scaling relationship limitations. The electrocatalytic performance is amplified by the subnanoscale catalyst to increase the partial current density of NH3 by 2.3 and 5.4 times compared to those of individual Co, Cu single‐atom/cluster catalysts (Co SCC, Cu SCC), respectively. This Co─Cu SCC is operated stably for 32 h in a long‐term bipolar membrane (BPM)‐based membrane electrode assembly (MEA) system for high‐concentration NH3 synthesis to produce over 1 m NH3 for conversion into high‐purity NH4Cl at 2.1 g day−1. [ABSTRACT FROM AUTHOR]

Electrochemical CO2 reduction reaction (CO2RR) occurring at the electrode/electrolyte interface is sensitive to both the potential and concentration polarization. Compared to static electrolysis at a fixed potential, pulsed electrolysis with alternating anodic and cathodic potentials is an intriguing approach that not only reconstructs the surface structure, but also regulates the local pH and mass transport from the electrolyte side in the immediate vicinity of the cathode. Herein, via a combined online mass spectrometry investigation with sub-second temporal resolution and 1-dimensional diffusion profile simulations, we reveal that heightened surface CO2 concentration promotes CO2RR over H2 evolution for both polycrystalline Ag and Cu electrodes after anodic pulses. Moreover, mild oxidative pulses generate a roughened surface topology with under-coordinated Ag or Cu sites, delivering the best CO2-to-CO and CO2-to-C2+ performance, respectively. Surface-enhanced infrared absorption spectroscopy elucidates the potential dependence of *CO and *OCHO species on Ag as well as the gradually improved *CO consumption rate over under-coordinated Cu after oxidative pulses, directly correlating apparent CO2RR selectivity with dynamic interfacial chemistry at the molecular level. How pulsed electrolysis impacts the electrochemical CO2 reduction reaction remains unclear. Here, authors present a molecular-level picture on the complex interactions between cathode surfaces, adsorbates, and local reaction environment to elucidate the promotional effect of pulsed electrolysis. [ABSTRACT FROM AUTHOR]

Single‐atom catalysts (SACs), featuring highly uniform active sites, tunable coordination environments, and synergistic effects with support, have emerged as one of the most efficient catalysts for various reactions, particularly for electrochemical CO2 reduction (ECR). However, the scalability of SACs is restricted due to the limited choice of available support and problems that emerge when preparing SACs by thermal deposition. Here, an in situ reconstruction method for preparing SACs is developed with a variety of atomic sites, including nickel, cadmium, cobalt, and magnesium. Driven by electricity, different oxygen‐containing metal precursors, such as MOF‐74 and metal oxides, are directly atomized onto nitrogen‐doped carbon (NC) supports, yielding SACs with variable metal active sites and coordination structures. The electrochemical force facilitates the in situ generation of bonds between the metal and the supports without the need for additional complex steps. A series of MNxOy (M denotes metal) SACs on NC have been synthesized and utilized for ECR. Among these, NiNxOy SACs using Ni‐MOF‐74 as a metal precursor exhibit excellent ECR performance. This universal and general SAC synthesis strategy at room temperature is simpler than most reported synthesis methods to date, providing practical guidance for the design of the next generation of high‐performance SACs. [ABSTRACT FROM AUTHOR]

CO2 electroreduction is a potential pathway to achieve net-zero emissions in the chemical industry. Yet, CO2 loss, resulting from (bi)carbonate formation, renders the process energy-intensive. Acidic environments can address the issue but at the expense of compromised product Faradaic efficiencies (FEs), particularly for multi-carbon (C2+) products, as rapid diffusion and migration of protons (H+) favors competing H2 and CO production. Here, we present a strategy of tuning the 2-position substituent length on benzimidazole (BIM)-based copper (Cu) coordination polymer (CuCP) precatalyst – to enhance CO2 reduction to C2+ products in acidic environments. Lengthening the substituent from H to nonyl enhances H+ diffusion retardation and decreases Cu-Cu coordination numbers (CNs), favoring further reduction of CO. This leads to a nearly 24× enhancement of selectivity towards CO hydrogenation and C-C coupling at 60 mA cm−2. We report the highest C2+ product FE of more than 70% at 260 mA cm−2 on pentyl-CuCP and demonstrate a CO2-to-C2+ single-pass conversion (SPC) of ~54% at 180 mA cm−2 using pentyl-CuCP in zero-gap electrolyzers. Acidic CO2 electroreduction suffers poor selectivity for multi-carbon products. Here, the authors report that lengthening the 2-position substituents of benzimidazole-based copper coordination polymer precatalysts retards H+ diffusion, reduces Cu-Cu coordination numbers, and promotes C-C coupling. [ABSTRACT FROM AUTHOR]

The electrocatalytic reduction of nitrate toward ammonia under mild conditions addresses many challenges of the Haber-Bosch reaction, providing a sustainable method for ammonia synthesis, yet it is limited by sluggish reduction kinetics and multiple competing reactions. Here, the titanium hydride electrocatalyst is synthesized by electrochemical hydrogenation reconstruction of titanium fiber paper, which achieves a large ammonia yield rate of 83.64 mg h−1 cm−2 and a high Faradaic efficiency of 99.11% with an ampere-level current density of 1.05 A cm−2 at −0.7 V versus the reversible hydrogen electrode. Electrochemical evaluation and kinetic studies indicate that the lattice hydrogen transfer from titanium hydride promotes the electrocatalytic performance of nitrate reduction reaction and the reversible equilibrium reaction between lattice hydrogen and activate hydrogen not only improves the electrocatalytic activity of nitrate reduction reaction but also demonstrates notable catalytic stability. These finding offers a universal design principle for metal hydrides as catalysts for effectively electrochemical ammonia production, highlighting their potential for sustainable ammonia synthesis. The electrocatalytic reduction of nitrate to ammonia offers a sustainable alternative to the Haber-Bosch process. Here, the authors report a lattice hydrogen transfer mechanism that enhances electrocatalytic activity by enabling reversible equilibrium reactions between lattice and active hydrogen. [ABSTRACT FROM AUTHOR]

This work presents the results of a study on the effect of ionic surfactants: cationic hexadecyltriammonium bromide (CTAB) and anionic sodium salt of sulfonic acid (1OSASS) on the Bi(III) electroreduction process in mixed aqueous–organic supporting electrolyte solutions containing methanol. This study showed that the composition of the supporting electrolyte solution, particularly the methanol and surfactant concentrations, significantly affects the mechanism and rate of the Bi(III) ion electroreduction. Analysis of the influence of the indicated factors on the mechanisms and kinetics of metal ion electroreduction can contribute not only to the optimization of industrial electrochemical processes but also to the development of innovative technological solutions, such as advanced electrochemical materials and novel sensors. In these experiments, an innovative electrode made of cyclic renewable liquid silver amalgam (R-AgLAFE) was used as a working electrode, which stands out among classic mercury electrodes (HMDE type) due to the significant reduction in mercury consumption while maintaining similar performance. [ABSTRACT FROM AUTHOR]

The electrochemical reduction of a series of nitro-substituted benzenesulfonyl chlorides is investigated. The results of the electrochemical study are analysed with the assistance of theoretical calculations. The study shows that the electron transfer mechanism depends on the position of the nitro substituent on the phenyl ring. The 3-nitrobenzenesulfonyl chloride follows a stepwise mechanism where the reduction leads to an intermediate radical anion. For the 4-nitrobenzenesulfonyl chloride, 2-nitrobenzenesulfonyl chloride, and 2,4-nitrobenzenesulfonyl chloride, the reduction follows a "sticky" dissociative mechanism, where the electron transfer and S–Cl bond cleavage are concerted. The dissociation products (arylsulfinyl radical and chloride anion) show strong interactions. The difference in behaviour is associated with the overlap of the π* orbital and the S–Cl σ* orbital for the latter three compounds. The through resonance stability of the arylsulfinyl radicals for the para and ortho nitro-substituted compounds facilitates the dissociation of the reduced structures. Upon reduction, the 3-nitrobenzenesulfonyl chloride and 4-nitrobenzenesulfonyl chloride, also produce the corresponding diaryl disulfones, which are easier to reduce that the parent molecules and hence induce an interesting autocatalytic mechanism. Such a mechanism, which depends on the concentration and the scan rate, does not take place with the 2-nitrobenzenesulfonyl chloride and 2,4-dinitrobenzenesulfonyl chloride due to the sterical hindrance of the nitro substituent at the ortho position, as it prevents the formation of the disulfones. [ABSTRACT FROM AUTHOR]

The attenuated total reflection-surface-enhanced infrared absorption spectroscopy (SEIRAS) activity of electrodeposited Cu nanoparticles on indium tin oxide-modified Si internal reflection elements is reported. The solution in the cell is easily, and repeatedly, exchanged between a copper deposition bath and a solution containing 4-methoxypyridine through the use of a flow-through spectroelectrochemical cell. 4-methoxypyridine is a convenient SEIRAS probe molecule exhibiting potential-dependent adsorption/desorption on the copper surface. Successive amounts of copper are deposited and then evaluated for electrochemical SEIRAS activity without the need to expose the Cu surface to ambient conditions. It is found that copper deposition charge densities of approximately 60 mC cm−2 exhibit the largest amplitude and most symmetric IR absorption peaks of the investigated electrodeposition conditions. Scanning electron microscopy images of the different Cu charge density films are correlated with the SEIRAS results and establish that close-packed two-dimensional, percolated arrays of oblate, ellipsoidal Cu nanoparticles are responsible for ideal SEIRAS performance and three-dimensional aggregates of larger particles should be avoided. Textured films of Cu nanoparticles are used to determine the adsorbed species present on the copper surface during CO2 electroreduction at low overpotentials. Evidence of adsorbed CO and COH is found at lower overpotentials than those described in previous reports. [ABSTRACT FROM AUTHOR]

The self-doping of oxygen vacancy and Ti3+ by electrochemical reduction (ER) method has been proved to be an effective means to improve the PEC performance of TiO2. However, the effect of the surface structure on ER treatment remains ambiguous. In this work, three kinds of nanostructured rutile TiO2 (nanowire arrays (TNWs), etched nanowire arrays (E-TNWs) and nanorod arrays (TNRs)) were reduced electrochemically to explore the factors influencing the ER process of rutile TiO2. The experimental results show that alkaline environment (1 M NaOH) is more conducive to the occurrence of ER reaction. And the reduced three kinds of nanostructured TiO2 photoanodes show a significantly higher photocurrent density of about 1.46, 1.65 and 1.45 mA cm−2 at 1.23 V vs. relative hydrogen electrode (RHE), respectively, which are 15, 16 and 1.1 times that of pristine TiO2. The different degrees of photocurrent density enhancement can be ascribed to the different degrees of electrochemical reduction of TiO2 with different crystallinity and exposed crystal facets as well as specific surface area. This study provides new insights into the mechanism of electrochemical reduction method. [ABSTRACT FROM AUTHOR]

This paper presents metal-free N–S co-doped catalysts that synthesize in the presence of different S sources such as thiourea and polythiophene (Ptyf). The composition, morphology, and structure of the obtained sample are measured by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), Brunauer–Emmett–Teller (BET) method, X-ray diffraction (XRD), UV–vis spectroscopy, Fourier transform ınfrared-attenuated total reflection spectroscopy (FTIR-ATR), and X-ray photoelectron spectroscopy (XPS). Although the characterization measurements showed that the fabricated catalysts had a similar elemental composition, the polythiophene-based catalysts retained their polymer properties such as active surface area, conductivity, and conjugated chains. This result enhances the adsorption of CO2 to the catalyst surface and promotes the reduction of CO2 effectively. The only product is HCOOH with a faradaic efficiency of 84% which was achieved on P-N/S2-rGO (P: pyrolysis) at -0.6 V (Ag/AgCl). [ABSTRACT FROM AUTHOR]

By adjusting the synthesis variation of hollow urchin-like Ni-NC(HU)-x catalyst, the content of pyridinic-N was adjusted, and the dual-atoms site was formed. Ni-NC(HU)-50 showed the best catalytic performance with FE CO of 97.2% at −0.9 V vs. RHE and sustains above 95% within 50 h. [Display omitted] Dual-atoms catalysts (DACs), while inheriting the advantages of maximum atom utilization ratio and excellent selectivity of single-atom catalysts (SACs), can better enhance the catalytic activity through the synergy of adjacent atoms. Therefore, DACs are considered to be very potential catalysts for CO 2 to CO conversion. Its catalytic activity is greatly influenced by the coordination environment and morphology. Here, hollow urchin-like Ni N C catalysts (Ni-NC(HU)-x, x = 100, 50, 25, 0) were synthesized using urchin-like nickel particles as template. By adjusting the amount of additional nitrogen source, the percentage content of pyridinic-N was adjusted as well as further affecting the coordination environment. Among them, Ni-NC(HU)-50, which had the highest content of pyridinic-N, formed a dual-atoms coordination structure and had the best catalytic performance that the CO Faradaic efficiency (FE CO) reached 97.2 % at −0.9 V vs. reversible hydrogen electrode (RHE) and sustained above 95 % within 50 h. In-situ attenuated total reflectance surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) and density functional theory (DFT) calculations showed that Ni-NC(HU)-50 exhibited the best performance of CO 2 reduction reaction (CO 2 RR) by lowering the *COOH formation free energy barrier and its favorable dual desorption mechanism of *CO L and *CO B. [ABSTRACT FROM AUTHOR]

[Display omitted] • Rare-earth Tb doped Pd 49 Ag 30 Te 4 alloy facilitates selective exposure of (1 1 1) crystal plane. • The doping of Tb accelerates electron transfer, promotes CO 2 adsorption as well as activation, and suppress H 2 evolution. • The introduction of Tb regulates d-band center of Pd 49 Ag 30 Te 4 , weakens the Pd − C bonding ability, and promotes the production of CO. Employing electric energy to convert carbon dioxide (CO 2) into valuable small molecules is a potentially practical method in energy storage and greenhouse gas alleviation. A huge challenge for electrocatalytic CO 2 reduction is to reduce overpotential to improve energy efficiency. Herein, we demonstrate that doping alloy Pd 49 Ag 30 Te 4 (PAT) with rare-earth element Tb is beneficial for selective exposure of (1 1 1) crystal plane, which is a highly active crystal plane for producing carbon monoxide (CO). The as-prepared Tb 2.9 PAT exhibited high electrocatalytic performance with 95.7 % CO faradic efficiency at − 0.8 V (vs RHE), far exceeding that of PAT, and coupled with good durability. In situ spectral study and theoretical calculations disclose that the introduction of Tb regulates the d-band center of PAT alloy, weakens the Pd − C bonding ability, and promotes the desorption of *CO in the rate-determining step. This study provides a method for doping induced selective exposure of crystal face, which provides new idea for improving catalytic performance. [ABSTRACT FROM AUTHOR]

The self-doping of oxygen vacancy and Ti3+ by electrochemical reduction (ER) method has been proved to be an effective means to improve the PEC performance of TiO2. However, the effect of the surface structure on ER treatment remains ambiguous. In this work, three kinds of nanostructured rutile TiO2 (nanowire arrays (TNWs), etched nanowire arrays (E-TNWs) and nanorod arrays (TNRs)) were reduced electrochemically to explore the factors influencing the ER process of rutile TiO2. The experimental results show that alkaline environment (1 M NaOH) is more conducive to the occurrence of ER reaction. And the reduced three kinds of nanostructured TiO2 photoanodes show a significantly higher photocurrent density of about 1.46, 1.65 and 1.45 mA cm−2 at 1.23 V vs. relative hydrogen electrode (RHE), respectively, which are 15, 16 and 1.1 times that of pristine TiO2. The different degrees of photocurrent density enhancement can be ascribed to the different degrees of electrochemical reduction of TiO2 with different crystallinity and exposed crystal facets as well as specific surface area. This study provides new insights into the mechanism of electrochemical reduction method. [ABSTRACT FROM AUTHOR]

Zinc metal stands out as a promising anode material due to its exceptional theoretical capacity, impressive energy density, and low redox potential. However, challenges such as zinc dendrite growth, anode corrosion, and side reactions in aqueous electrolytes significantly impede the practical application of zinc metal anodes. Herein, 3‐(1‐pyridinio)‐1‐propanesulfonate (PPS) is introduced as a zwitterionic additive to achieve long‐term and highly reversible Zn plating/stripping. Due to the orientation polarization with the force of electric field, PPS additive with π–π conjugated pyridinio cations and strong coordination ability of sulfonate anion tends to generate a dynamic adsorption layer and build a unique water–poor interface. PPS with steric hindrance effect and strong coordination ability can attract solvated Zn2+, thereby promoting the desolvation process. Moreover, by providing a large number of nucleation sites and inducing zinc ion flow, the preferred orientation of the (002) crystal plane can be achieved. Therefore, the interfacial electrochemical reduction kinetics is regulated and uniform zinc deposition is ensured. Owing to these advantages, the Zn//Zn symmetrical cell with PPS additive exhibits remarkable cycling stability exceeding 2340 h (1 mA cm−2 and 1 mA h cm−2). The Zn//V2O5 full cell also delivers stable cycling for up to 6000 cycles. [ABSTRACT FROM AUTHOR]

Emerging as a new class of two‐dimensional materials with atomically thin layers, MBenes have great potential for many important applications such as energy storage and electrocatalysis. Toward mitigating carbon footprint, there has been increasing interest in CO2/CO conversion on MBenes, but mostly focused on C1 products. C2+ chemicals generally possess higher energy densities and wider applications than C1 counterparts. However, C–C coupling is technically challenging because of high energy requirement and currently few catalysts are suited for this process. Here, we explore electrochemical CO reduction reaction to C2 chemicals on Mo2B2O2 MBene via density‐functional theory calculations. Remarkably, the most favorable CO–COH coupling is revealed to be a spontaneous and barrierless process, making Mo2B2O2 an efficient catalyst for C–C coupling. Among C1 and C2 chemicals, ethanol is predicted to be the primary product. Furthermore, by charge and bond analysis, it is unraveled that there exist significantly more unbonded electrons in the C atom of intermediate *COH than other C1 intermediates, which is responsible for the facile C–C coupling. From an atomic scale, this work provides microscopic insight into C–C coupling process and suggests Mo2B2O2 a promising catalyst for electrochemical CO reduction to C2 chemicals. [ABSTRACT FROM AUTHOR]

The discharge capacities and rate capability of TiNb2O7 powders were enhanced through the additional postreduction treatment. X‐ray photoelectron spectroscopy and electron paramagnetic resonance results confirmed the formation of oxygen vacancies in TiNb2O7 powders after a reduction treatment. The appearance of oxygen vacancies in TiNb2O7 powders formed the impurity level in the forbidden gap and decreased the bandgap values of TiNb2O7. Compared with the pristine TiNb2O7 powders, when TiNb2O7 powders were reduced at 400°C for 40 min, the charge transfer resistance of prepared samples was reduced from 43.67 to 19.35 Ω, and the pseudocapacitive contribution of TiNb2O7 was increased from 44% to 59%. In addition, the discharge capacities at 0.1 and 20 C of prepared batteries were increased by 10.84% and 105.85%, respectively. On the other hand, increasing the temperature in the reduction treatment caused the formation of Ti4+/Ti3+ and Nb5+/Nb4+ pairs and decreased the amounts of available redox couples, thereby deteriorating the electrochemical performance of prepared batteries. The results in the present study revealed that the discharge capacities and rate capability of TiNb2O7 powders were enhanced through a postreduction treatment. [ABSTRACT FROM AUTHOR]

Efficient electrochemical CO2 reduction reaction (CO2RR) requires advanced gas‐diffusion electrodes (GDEs) with tunned microenvironment to overcome low CO2 availability in the vicinity of catalyst layer. Herein, for the first time, pyridine‐containing microgels‐augmented CO2 availability is presented in Cu2O‐based GDE for high‐rate CO2 reduction to ethylene, owing to the presence of CO2‐phil microgels with amine moieties. Microgels as three‐dimensional polymer networks act as CO2 micro‐reservoirs to engineer the GDE microenvironment and boost local CO2 availability. The superior ethylene production performance of the GDE modified by 4‐vinyl pyridine microgels, as compared with the GDE with diethylaminoethyl methacrylate microgels, indicates the bifunctional effect of pyridine‐based microgels to enhance CO2 availability, and electrocatalytic CO2 reduction. While the Faradaic efficiency (FE) of ethylene without microgels was capped at 43% at 300 mA cm−2, GDE with the pyridine microgels showed 56% FE of ethylene at 700 mA cm−2. A similar trend was observed in zero‐gap design, and GDEs showed 58% FE of ethylene at −4.0 cell voltage (>350 mA cm−2 current density), resulting in over 2‐fold improvement in ethylene production. This study showcases the use of CO2‐phil microgels for a higher rate of CO2RR‐to‐C2+, opening an avenue for several other microgels for more selective and efficient CO2 electrolysis. [ABSTRACT FROM AUTHOR]

Electrochemical CO2 reduction reaction (CO2RR) to produce value‐added multi‐carbon chemicals has been an appealing approach to achieving environmentally friendly carbon neutrality in recent years. Despite extensive research focusing on the use of CO2 to produce high‐value chemicals like high‐energy‐density hydrocarbons, there have been few reports on the production of propane (C3H8), which requires carbon chain elongation and protonation. A rationally designed 0D/2D hybrid Cu2O anchored‐Ti3C2Tx MXene catalyst (Cu2O/MXene) is demonstrated with efficient CO2RR activity in an aqueous electrolyte to produce C3H8. As a result, a significantly high Faradaic efficiency (FE) of 3.3% is achieved for the synthesis of C3H8 via the CO2RR with Cu2O/MXene, which is ≈26 times higher than that of Cu/MXene prepared by the same hydrothermal process without NH4OH solution. Based on in‐situ attenuated total reflection‐Fourier transform infrared spectroscopy (ATR‐FTIR) and density functional theory (DFT) calculations, it is proposed that the significant electrocatalytic conversion originated from the synergistic behavior of the Cu2O nanoparticles, which bound the *C2 intermediates, and the MXene that bound the *CO coupling to the C3 intermediate. The results disclose that the rationally designed MXene‐based hybrid catalyst facilitates multi‐carbon coupling as well as protonation, thereby manipulating the CO2RR pathway. [ABSTRACT FROM AUTHOR]

Electrolyte plays crucial roles in electrochemical CO2 reduction reaction (e‐CO2RR), yet how it affects the e‐CO2RR performance still being unclarified. In this work, it is reported that Sn‐Zn hybrid oxide enables excellent CO2‐to‐HCOO− conversion in KHCO3 with a HCOO− Faraday efficiency ≈89%, a yield rate ≈0.58 mmol cm−2 h−1 and a stability up to ≈60 h at −0.93 V, which are higher than those in NaHCO3 and K2SO4. Systematical characterizations unveil that the surface reconstruction on Sn‐Zn greatly depends on the electrolyte using: the Sn‐SnO2/ZnO, the ZnO encapsulated Sn‐SnO2/ZnO and the Sn‐SnO2/Zn‐ZnO are reconstructed on the surface by KHCO3, NaHCO3 and K2SO4, respectively. The improved CO2‐to‐HCOO− performance in KHCO3 is highly attributed to the reconstructed Sn‐SnO2/ZnO, which can enhance the charge transportation, promote the CO2 adsorption and optimize the adsorption configuration, accumulate the protons by enhancing water adsorption/cleavage and limit the hydrogen evolution. The findings may provide insightful understanding on the relationship between electrolyte and surface reconstruction in e‐CO2RR and guide the design of novel electrocatalyst for effective CO2 reduction. [ABSTRACT FROM AUTHOR]

Carbon capture and utilization (CCU) technologies present a promising solution for converting CO2 emissions into valuable products. Here we show how amines, such as monoethanolamine (MEA) and 2-amino-2-methyl-1-propanol (AMP), influence the electrochemical CO2 reduction process in an integrated CCU system. Using in situ spectroscopic techniques, we identify the key roles of carbamate bond strength, proton shuttling, and amine structure in dictating reaction pathways on copper (Cu) and lead (Pb) electrodes. Our findings demonstrate that on Cu electrodes, surface blockage by ammonium species impedes CO₂ reduction, whereas on Pb electrodes, proton shuttling enhances the production of hydrocarbon products. This study provides additional insights into optimizing CCU systems by tailoring the choice of amines and electrode materials, advancing the selective conversion of CO₂ into valuable chemicals. Integrated carbon capture and utilization (CCU) systems offer a sustainable approach to converting CO₂ emissions into valuable chemicals. Here, the authors report the choice of amine and electrode materials significantly impact the efficiency and selectivity of CO2 reduction in CCU processes. [ABSTRACT FROM AUTHOR]

Electrochemical conversion of nitrate (NO3−) to ammonia (NH3) is a potential way to produce green NH3 and remediate the nitrogen cycle. In this paper, an efficient catalyst of spherical CuO made by stacking small particles with oxygen‐rich vacancies is reported. The NH3 yield and Faraday efficiency are 15.53 mg h−1 mgcat−1 and 90.69%, respectively, in a neutral electrolyte at a voltage of ‐0.80 V (vs. reversible hydrogen electrode). The high activity of the electrodes results from changes in the phase and structure during electrochemical reduction. Structurally, there is a shift from a spherical structure with dense accumulation of small particles to a layered network structure with uniform distribution of small particles stacked on top of each other, thus exposing more active sites. Furthermore, in terms of phase, the electrode transitions from CuO to Cu/Cu(OH)2. Density functional theory calculations showed that Cu(OH)2 formation enhances NO3‐ adsorption. Meanwhile, the Cu(OH)2 can inhibit the competing hydrogen evolution reaction, while the formation of Cu (111) crystal surfaces facilitates the hydrogenation reaction. The synergistic effect between the two promotes the NO3‐ to NH3. Therefore, this study provides a new idea and direction for Cu‐based oxides in electrocatalytic NH3 production. [ABSTRACT FROM AUTHOR]

Transition metal‐nitrogen‐carbon (M‐N‐C) catalysts have emerged as promising candidates for electrocatalytic CO2 reduction reaction (CO2RR) due to their uniform active sites and high atomic utilization rate. However, poor efficiency at low overpotentials and unclear reaction mechanisms limit the application of M‐N‐C catalysts. In this study, Fe‐N‐C catalysts are developed by incorporating S atoms onto ordered hierarchical porous carbon substrates with a molecular iron thiophenoporphyrin. The well‐prepared FeSNC catalyst exhibits superior CO2RR activity and stability, attributes to an optimized electronic environment, and enhances the adsorption of reaction intermediates. It displays the highest CO selectivity of 94.0% at −0.58 V (versus the reversible hydrogen electrode (RHE)) and achieves the highest partial current density of 13.64 mA cm−2 at −0.88 V. Furthermore, when employed as the cathode in a Zn‐CO2 battery, FeSNC achieves a high‐power density of 1.19 mW cm−2 and stable charge–discharge cycles. Density functional theory calculations demonstrate that the incorporation of S atoms into the hierarchical porous carbon substrate led to the iron center becoming more electron‐rich, consequently improving the adsorption of the crucial reaction intermediate *COOH. This study underscores the significance of hierarchical porous structures and heteroatom doping for advancing electrocatalytic CO2RR and energy storage technologies. [ABSTRACT FROM AUTHOR]

[Display omitted] Conversion of NO 3 − to NH 3 proceeds stepwise in natural system under two different enzymes involving intermediate NO 2 −. Artificial electro-driven NO 3 − reduction also faces the obstacle of low faradaic efficiency due to insufficient utilization of this intermediate. Herein, we demonstrate a bimetallic COF-based electrocatalyst for the cascade catalysis of NO 3 −-to-NO 2 −-to-NH 3 for the first time. TpBpy-Cu 2 Co 4 exhibits a significantly improved performance, with an enhancement factor of 1.4–2 compared to monometallic TpBpy-M. The NH 3 yield rate achieves 25.6 mg h−1 mg cat. −1 at −0.55 V vs RHE over TpBpy-Cu 2 Co 4 , together with excellent faradaic efficiency (93.4 %). This achievement demonstrates cascade catalysis between Co and Cu units, and their distinct roles are investigated through electrochemical experiments and theory calculations. In electrocatalytic process, Cu site facilities *NO 3 -to-*NO 3 H step, while the Co site significantly decreases the energy barrier of *NHOH-to-*NH. The present work provides a valuable inspiration in designing efficient catalysts for cascade reaction. [ABSTRACT FROM AUTHOR]

Electrocatalytic CO2 reduction technology offers an effective way to convert CO2 into valuable chemicals and fuels, presenting a sustainable solution for carbon emissions. Current electrocatalytic CO2 reduction technologies encounter significant issues such as salt precipitation and hydrogen evolution, which prevent energy conversion efficiency, selectivity, current density, and stability from simultaneously meeting industrial standards. In recent years, researchers have discovered that increasing the CO2 pressure on the gas supply could enhance the coverage of the catalyst and activate more CO2 reduction reaction sites on the catalyst surface, which provides a practical and effective approach for optimizing the energy conversion and mass transfer. In this review, we provide a comprehensive review of the development history and current status of high-pressure CO2 electrocatalytic reduction technology, focusing on its reaction devices, catalytic performance, and reaction mechanisms. Furthermore, we summarize and offer insights into the most promising research avenues to propel the field forward. Highlights: 1. A briefly discussion on the challenges faced by CO2 electrochemical reduction. 2. The state-of-the-art progress of the high-pressure CO2 electrochemical reduction for chemical synthesis is summarized. 3. The bottlenecks of current high-pressure CO2 electrochemical reduction technology are highlighted and potential optimization strategies are proposed. [ABSTRACT FROM AUTHOR]

It is well accepted that the Cu(100) surface is catalytic active for C–C coupling in CO2 reduction. However, the (100) surface is less active for the preceding CO* formation process and, most importantly, less stable than other surfaces. In this work, we investigate the relationship between catalytic effects and general factors such as coordination number and spacing (strain) of the Cu surface atoms. We find that the former affects the CO* formation only and the latter affects both the CO* formation and the subsequent C–C coupling. Among all the strained surfaces with larger atomic spacing, the more stable Cu(111) surface is extraordinary and outperforms Cu(100) and the high index surfaces for CO2 reduction to C2 on Cu. [ABSTRACT FROM AUTHOR]

Molten CaCl2–CaO system is a suitable electrolyte medium for reducing metal oxides to metal by in-situ electro-generated calcium metal. The graphite anode, which acts as a reactive anode in this melt, leads to several parasitic reactions and decreases the current efficiency. The present study investigates the usage of platinum anode towards the direct oxide electrochemical reduction of ThO2 and NiO by electro-generated calcium in CaCl2–1 wt % CaO melt at 900 °C. Primarily, the anodic behavior of platinum electrode was investigated using electrochemical techniques such as linear sweep voltammetry, potentiodynamic polarization, electrochemical impedance spectroscopy, cyclic voltammetry and potentiostatic electrolysis in CaCl2–CaO melt. Platinum exhibited the most anodic polarization potential, positive corrosion potential, and highest oxidation resistance compared to nickel and gold. It also showed a clearly demarcated potential window for oxygen evolution and much better physico-chemical stability compared to gold electrode. Electro-calciothermic reduction experiments conducted with ThO2 and NiO cathodes using platinum anode demonstrated the feasibility of metallization, and platinum's mass loss rate in these experiments was found to be much less (in the order of ~ 0.016 g cm−2 h−1). The study showed that platinum could be used as an anode in the electrochemical reduction of solid metal oxides in CaCl2–1 wt % CaO melt with minimal mass loss. [ABSTRACT FROM AUTHOR]

A Ce-Cu 2+1 O/Cu 3 VO 4 -CF catalyst was successfully fabricated for efficient electrocatalytic nitrate reduction to ammonia, which demonstrates remarkable performance under alkaline conditions, achieving an NH 3 Faradaic efficiency (FE) of 93.7% at −0.5 V (vs. RHE), with an NH 3 production rate of 18.905 mg/h cm−2. [Display omitted] • A Ce doped Cu 2+1 O/Cu 3 VO 4 -CF electrocatalyst is first reported. • Ce-Cu 2+1 O/Cu 3 VO 4 -CF shows superior electrocatalytic NO 3 RR performance. • Ce-doping adjusts the density of states of the catalyst and creates more O v , which promotes the NO 3 RR activity. • DFT calculations further reveal the changes the d-band center and the rate-degerming step. The electrocatalytic nitrate reduction to ammonia reaction (ENO 3 RR) holds great potential as a cost-effective method for synthesizing ammonia. This work designed a cerium (Ce) doped Cu 2+1 O/Cu 3 VO 4 catalyst. The coupling of vanadium-based oxides with Cu 2+1 O effectively adjusts the catalyst's electronic structure, addressing the inherent issues of limited activity and low conductivity in typical copper-based oxides; moreover, Ce doping generates oxygen vacancies (O v), providing more active sites and thereby enhancing the ENO 3 RR performance. The catalyst exhibits superior NH 3 Faradaic efficiency (93.7 %) with a NH 3 yield of 18.905 mg h−1 cm−2 at −0.5 V vs. RHE under alkaline conditions. This study provides guidance for the design of highly efficient catalysts for ENO 3 RR. [ABSTRACT FROM AUTHOR]

[Display omitted] Production of C 2 chemicals (such as C 2 H 4 , C 2 H 5 OH, etc.) from CO 2 electroreduction reaction (CO 2 ER) has been regarded as a promising route to solve the environmental problems and energy crisis. In this work, mesoporous Cu 2 O microspheres of ca. 700 nm diameter size with low crystallinity were fabricated to enable efficient conversion of CO 2 to C 2 chemicals by electrocatalytic reduction. It is revealed that compared with bulk Cu 2 O, the obtained mesoporous Cu 2 O microspheres have larger surface area, more grain boundaries and defects (unsaturated coordination sites), which facilitate the adsorption and stabilization of the important intermediates, such as *CO, on the route to C 2 chemicals formation. As a result, the Faraday efficiency (FE) of C 2 products reaches as high as 82.6 % and 78.5 % in an H-cell and a flow cell, respectively. In situ Raman and FT-IR spectra reveal that during CO 2 ER test there exists abundant *CO on the mesoporous Cu 2 O surface, thus increasing the opportunity of C C coupling. And the high coverage of *CO on catalyst surface during CO 2 ER protects and stabilizes the oxidation state of Cu species. This work demonstrates an effective strategy to introduce mesoporous structures and decreased crystallinity for improving the performance of CO 2 ER to C 2 products. [ABSTRACT FROM AUTHOR]

Industrial CO2 electrolysis via electrochemical CO2 reduction has achieved progress in alkaline solutions, while the same reaction in acidic solution remains challenging because of severe hydrogen evolution side reactions, acid corrosion, and low target product selectivity. Herein, an industrial acidic CO2 electrolysis to pure HCOOH system is realized in a proton-exchange-membrane electrolyzer using an acid-tolerant Bi-based metal-organic framework guided by a Pourbaix diagram. Significantly, the Faradaic efficiency of HCOOH synthesis reaches 95.10% at a large current density of 400 mA/cm2 with a high CO2 single-pass conversion efficiency of 64.91%. Moreover, the proton-exchange-membrane device also achieves an industrial-level current density of 250 mA/cm2 under a relatively low voltage of 3.5 V for up to 100 h with a Faradaic efficiency of 93.5% for HCOOH production, which corresponds to an energy consumption of 200.65 kWh/kmol, production rate of 12.1 mmol/m2/s, and an energy conversion efficiency of 38.2%. These results will greatly aid the contemporary research moving toward commercial implementation and success of CO2 electrolysis technology. This work develops an industrial-level CO2 electrolysis system for formic acid production by constructing a proton exchange membrane electrolyzer with an acid-tolerant Bismuth metal-organic framework. [ABSTRACT FROM AUTHOR]

Silver-based catalytic materials have garnered considerable attention due to their high selectivity towards carbon monoxide (CO) in the electrochemical reduction (ECR) of CO2. However, the fabrication of silver-based ECR catalysts with high product selectivity and low competitive reaction activity using facile methods remains challenging. This study employed in situ electrochemical reconstruction to design high-performance silver-based catalytic materials for ECR, exploring performance enhancement mechanisms. Low-temperature electrochemical reconstruction was used to prepare silver-based catalysts, and the effects of metal ion chelating agents including ethylenediaminetetraacetic acid, citric acid, and sodium citrate were also investigated. Results showed that Ag-SC, namely the catalysts fabricated with sodium citrate as chelating agent, exhibited highly selective CO production, with faradaic efficiency of 93.23% at −0.85 V (versus reversible hydrogen electrode, RHE) and CO partial current density of −7.92 mA cm−2. Electrochemical impedance analysis confirmed low electron transfer resistance of Ag-SC, with 14.54 Ω, indicating superior electron transfer capability, and high ECR activity. Ag-SC also demonstrated excellent hydrophobicity, suppressing the competitive hydrogen evolution reaction and enhancing CO selectivity. In situ electrochemical reconstruction thus offers a simple, low-cost method for preparing silver-based catalysts tailored for ECR, with practical implications for electrode fabrication and catalytic material design. [ABSTRACT FROM AUTHOR]

The molten Li2CO3 transformation of CO2 to oxygen and graphene nanocarbons (GNCs), such as carbon nanotubes, is a large scale process of CO2 removal to mitigate climate change. Sustainability benefits include the stability and storage of the products, and the GNC product value is an incentive for carbon removal. However, high Li2CO3 cost and its competitive use as the primary raw material for EV batteries are obstacles. Common alternative alkali or alkali earth carbonates are ineffective substitutes due to impure GNC products or high energy limitations. A new decarbonization chemistry utilizing a majority of SrCO3 is investigated. SrCO3 is much more abundant, and an order of magnitude less expensive, than Li2CO3. The equivalent affinities of SrCO3 and Li2CO3 for absorbing and releasing CO2 are demonstrated to be comparable, and are unlike all the other alkali and alkali earth carbonates. The temperature domain in which the CO2 transformation to GNCs can be effective is <800 °C. Although the solidus temperature of SrCO3 is 1494 °C, it is remarkably soluble in Li2CO3 at temperatures less than 800 °C, and the electrolysis energy is low. High purity CNTs are synthesized from CO2 respectively in SrCO3 based electrolytes containing 30% or less Li2CO3. The transformation of CO2 to oxygen and graphene nanocarbons using lithium carbonate as an electrolyte is a promising, large-scale process for CO2 removal and valorization, but lithium carbonate is already in high demand as an important battery material. Here, the authors report the use of strontium carbonate as an alternative electrolyte in the electrochemical reduction of CO2 to carbon nanotubes. [ABSTRACT FROM AUTHOR]

The advancement of cost-effective, high-performance catalysts for both electrochemical oxygen reduction reactions (ORRs) and oxygen evolution reactions (OERs) is crucial for the widespread implementation of metal–air batteries. In this research, we fabricated leaf-like N-doped carbon frames embedded with Co nanoparticles by pyrolyzing a ZIF-L/carbon nanofiber (ZIF-L/CNF) composite. Consequently, the optimized ZIF-L/CNF-700 catalyst exhibit exceptional catalytic activities in both ORRs and OERs, comparable to the benchmark 20 wt% Pt/C and RuO2. Addressing the issue of diminished cycle performance in the Zn–air battery cycle process, further detailed investigations into the post-electrolytic composition reveal that both the carbon framework and Co nanoparticles undergo partial oxidation during both OERs and ORRs. Owing to the varying local pH on the catalyst surface due to the consumption and generation of OH− by OERs and ORRs, after OERs, the product is reduced-size Co particles, while after ORRs, the product is outer-layer Co(OH)2-enveloping Co particles. [ABSTRACT FROM AUTHOR]

[Display omitted] • An efficient descriptor of catalytic activity (ΔE NH2*) was developed. • A descriptor-based design principle was proposed. • Constructing bimetallic MBene can promote the NRR catalytic performance. • Bimetallic MBene break linear scaling relations between ΔE NHNH2** and ΔE NH2NH2**. Electrocatalytic nitrogen reduction reaction (NRR) is one of the most promising approaches to achieving green and efficient NH 3 production. However, the designs of efficient NRR catalysts with high activity and selectivity still are severely hampered by inherent linear scaling relations among the adsorption energies of NRR intermediates. Herein, the properties of ten M 3 B 4 type MBenes have been initially investigated for efficient N 2 activation and reduction to NH 3 via first-principles calculations. We highlight that Cr 3 B 4 MBene possesses remarkable NRR activity with a record-low limiting potential (−0.13 V). Then, this work proposes descriptor-based design principles that can effectively evaluate the catalytic activity of MBenes, which have been further employed to design bimetallic M 2 M'B 4 MBenes. As a result, 5 promising candidates including Ti 2 YB 4 , V 2 YB 4 , V 2 MoB 4 , Nb 2 YB 4 , and Nb 2 CrB 4 with excellent NRR performance have been extracted from 20 bimetallic MBenes. Further analysis illuminates that constructing bimetallic MBenes can selectively tune the adsorption strength of NHNH 2 ** and NH 2 NH 2 **, and break the linear scaling relations between their adsorption energies, rendering them ideal for NRR. This work not only pioneers the application of MBenes as efficient NRR catalysts but also proposes rational design principles for boosting their catalytic performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Newly synthesized Cu 3 N catalyst was employed for electrocatalytic nitrate reduction and ammonia production. • The strategy of balancing *H 2 O and *NO 3 intermediates adsorption for enhanced NO 3 RR was highlighted. • In-situ and ex-situ analysis verify the potential driven reconstruction and rehabilitation of Cu 3 N. Nitrate in surface and underground water caused systematic risk to the ecological environment. The electrochemically reduction of nitrate into ammonia (NO 3 RR), offering a sustainable route for nitrate containing wastewater treatment and ammonia fertilizer conversion. Exploration of catalyst with improved catalytic activity with lower energy barriers is still challenging. Here, we report a copper nitride (Cu 3 N) catalyst with moderate *NO x and *H 2 O intermediates adsorptions showed enhanced NO 3 RR performance. Density functional theory calculations reveals that the unique electronic structure of Cu 3 N provides efficient active sites for NO 3 RR, thus enabled balanced adsorption of *NO 3 and *H 2 O (ΔE descriptor), sufficient active hydrogen, and moderate intermediate (*NO 3 → HNO 3 , *NH 2 →*NH 3) adsorption energy. Notably, the in-situ analysis technology revealed potential-driven reconstruction and rehabilitation of Cu 3 N, forming possible nitrogen vacancy, thus implied for better mechanism understanding. The NO 3 RR activity of Cu 3 N surpasses that of most recent catalysts and demonstrates superior stability and implies the application for NH 4 + fertilizer recovery, which maintaining an NH 3 Faradaic efficiency of 93.1 % and high yield rate of 2.9 mg cm2h−1 at −0.6 V versus RHE. These findings broaden the application scenarios of Cu 3 N catalyst for ammonia synthesis and provide strategy on improving NO 3 RR performance. [ABSTRACT FROM AUTHOR]

The discovery and development of efficient technologies that enable the use of CO2 as a starting material for chemical synthesis (at scale) is probably one of the biggest scientific challenges of our time. But a key question is if the cure will not be worse than the disease? In this work, the economic feasibility of the electrochemical reduction of CO2 to ethylene is assessed and it is demonstrated that from a Capital expenditure and Operational expenditure point of view the electrochemical production of ethylene from CO2 is not feasible under the current market conditions. Even in the case that the renewable electricity price would be zero, the feasibility is hampered by the state-of-the-art catalyst performance (selectivity) and the cost of the electrochemical reactor. Turning the installation on and off, if this would be even practically possible, is not interesting because our study shows that because of the high Capital expenditure, the payback time of the process would become unacceptably high. Finally, because of the high electricity requirement, this Carbon Capture and Utilization process has a lower CO2 avoidance potential than the substitution of gray electricity by green electricity. This means that today the available green electricity would best be used to close coal and gas based power plants instead of powering the electrochemical conversion of CO2 to ethylene. [ABSTRACT FROM AUTHOR]

Ammonia (NH3) is a crucial industrial raw material, but the traditional Haber-Bosch process is energy-intensive and highly polluting. Electrochemical methods for synthesizing ammonia using nitric oxide (NO) as a precursor offer the advantages of operating under ambient conditions and achieving both NO reduction and resource utilization. Defect engineering enhances electrocatalytic performance by modulating electronic structures and coordination environments. In this brief review, the catalytic reaction mechanism of electrocatalytic NO reduction to NH3 is elucidated, with a focus on synthesis strategies involving vacancy defects and doping defects. From this perspective, the latest advances in various catalytic reduction systems for nitric oxide reduction reaction (NORR) are summarized and synthesized. Finally, the research prospects for NO reduction to NH3 are discussed. [ABSTRACT FROM AUTHOR]

Ammonia (NH3) is a crucial industrial raw material, but the traditional Haber-Bosch process is energy-intensive and highly polluting. Electrochemical methods for synthesizing ammonia using nitric oxide (NO) as a precursor offer the advantages of operating under ambient conditions and achieving both NO reduction and resource utilization. Defect engineering enhances electrocatalytic performance by modulating electronic structures and coordination environments. In this brief review, the catalytic reaction mechanism of electrocatalytic NO reduction to NH3 is elucidated, with a focus on synthesis strategies involving vacancy defects and doping defects. From this perspective, the latest advances in various catalytic reduction systems for nitric oxide reduction reaction (NORR) are summarized and synthesized. Finally, the research prospects for NO reduction to NH3 are discussed. [ABSTRACT FROM AUTHOR]

The intensive study of electrochemical CO2 reduction reaction (CO2RR) has resulted in numerous highly selective catalysts, however, most of these still exhibit uncontrollable selectivity. Here, it is reported for the first time the controllable CH4/C2H4 selectivity by modulating the electronic states of Cu incorporated in metal‐organic frameworks with different functional ligands, achieving a Faradaic efficiency of 58% for CH4 on Cu‐incorporated UiO‐66‐H (Ce) composite catalysts, Cu/UiO‐66‐H (Ce) and that of 44% for C2H4 on Cu/UiO‐66‐F (Ce). In situ measurements of Raman and X‐ray absorption spectra revealed that the electron‐withdrawing ability of the ligand side group controls the product selectivity on MOFs through the modulation of the electronic states of Cu. This work opens new prospects for the development of MOFs as a platform for the tailored tuning of selectivity in CO2RR. [ABSTRACT FROM AUTHOR]

Ammonia (NH3) is a crucial industrial raw material, but the traditional Haber-Bosch process is energy-intensive and highly polluting. Electrochemical methods for synthesizing ammonia using nitric oxide (NO) as a precursor offer the advantages of operating under ambient conditions and achieving both NO reduction and resource utilization. Defect engineering enhances electrocatalytic performance by modulating electronic structures and coordination environments. In this brief review, the catalytic reaction mechanism of electrocatalytic NO reduction to NH3 is elucidated, with a focus on synthesis strategies involving vacancy defects and doping defects. From this perspective, the latest advances in various catalytic reduction systems for nitric oxide reduction reaction (NORR) are summarized and synthesized. Finally, the research prospects for NO reduction to NH3 are discussed. [ABSTRACT FROM AUTHOR]

Ammonia (NH3) is a crucial industrial raw material, but the traditional Haber-Bosch process is energy-intensive and highly polluting. Electrochemical methods for synthesizing ammonia using nitric oxide (NO) as a precursor offer the advantages of operating under ambient conditions and achieving both NO reduction and resource utilization. Defect engineering enhances electrocatalytic performance by modulating electronic structures and coordination environments. In this brief review, the catalytic reaction mechanism of electrocatalytic NO reduction to NH3 is elucidated, with a focus on synthesis strategies involving vacancy defects and doping defects. From this perspective, the latest advances in various catalytic reduction systems for nitric oxide reduction reaction (NORR) are summarized and synthesized. Finally, the research prospects for NO reduction to NH3 are discussed. [ABSTRACT FROM AUTHOR]

The development of copper nanoparticle (CuNP)-based catalysts for the electrochemical reduction of carbon dioxide (ECO2-R) offers a promising approach to enhance its transformation into other industrially significant compounds. This study reports ECO2-R at -1.3 V vs RHE using CuNPs and catalytic inks composed of CuNPs and ionic liquids (ILs), observing significant differences in the selectivity of each catalyst. Specifically, CuNPs alone show a preference for producing ethylene and aqueous products, such as formic acid, ethanol, and formaldehyde. In contrast, the addition of ILs to the catalytic system redirects selectivity toward gaseous products, with methane being the main product. These findings highlight the potential to optimize catalyst composition to tailor the selectivity of CO2 conversion processes. ILs modify the catalytic environment and influence reaction pathways, enabling the selection of specific products. [ABSTRACT FROM AUTHOR]

Electrochemical reduction of carbon dioxide to produce high-value ethylene is often limited by poor selectivity and yield of multi-carbon products. To address this, we propose a cyanamide-coordinated isolated copper framework with both metallic copper (Cu0) and charged copper (Cu1+) sites as an efficient electrocatalyst for the reduction of carbon dioxide to ethylene. Our operando electrochemical characterizations and theoretical calculations reveal that copper atoms in the Cuδ+NCN complex enhance carbon dioxide activation by improving surface carbon monoxide adsorption, while delocalized electrons around copper sites facilitate carbon-carbon coupling by reducing the Gibbs free energy for *CHC formation. This leads to high selectivity for ethylene production. The Cuδ+NCN catalyst achieves 77.7% selectivity for carbon dioxide to ethylene conversion at a partial current density of 400 milliamperes per square centimeter and demonstrates long-term stability over 80 hours in membrane electrode assembly-based electrolysers. This study provides a strategic approach for designing catalysts for the electrosynthesis of value-added chemicals from carbon dioxide. This study reports a cyanamide-framework stabilized multivalent copper catalyst for efficient electrochemical reduction of carbon dioxide to ethylene with 77.7% selectivity at 400 mA cm−2, offering a rational strategy for CO2 conversion. [ABSTRACT FROM AUTHOR]

The electrochemical reduction of CO2 (ERCO2) to valuable chemicals such as acetic acid/acetate offers a promising route to revolutionize chemical production and enhance sustainability. Here, we report the hydrothermal preparation of an electrocatalyst consisting of copper/titanium dioxide/reduced graphene oxide (Cu‐TiO2/rGO) for ERCO2 in aqueous medium. The metal‐support (TiO2/rGO) was pre‐synthesized by combining an aqueous solution of TiO2 and GO in an autoclave at 150 °C for 20 h. Then TiO2/rGO was added to synthesized Cu colloid formed through the reduction of copper (II) nitrate trihydrate resulting in the formation of Cu‐TiO2/rGO. The Cu‐TiO2/rGO hybrid nanocomposite was fully characterized using spectroscopic and microscopic techniques. This study explored the versatility of the rotating ring‐disc electrode (RRDE) as an in situ electroanalytical tool for the selective detection of products formed during ERCO2. The well‐designed hybrid electrocatalyst, containing Cu0/Cu+ active sites, facilitated the eight‐electron transfer for acetic acid (AA) formation at low potentials. AA formation was detected on the RRDE and validated by conventional NMR and HPLC techniques. This work highlights and expands the scope of selective hydrogenation of CO2 towards value‐added products. [ABSTRACT FROM AUTHOR]

In recent years, the electrocatalytic reduction of nitrate to ammonia (NRA) has garnered significant research attention. However, the complex multi-step proton–electron transfer process often results in various by-products, limiting NH3 production. Therefore, designing and developing highly active and selective electrocatalysts for efficient NRA is crucial. This study proposes a method to construct Cu/Cu2O nanosheet arrays with heterogeneous interfaces and oxygen vacancies on copper foam surfaces through electrochemical reduction. The interface coupling between Cu and Cu2O significantly optimizes the catalyst's surface electronic structure, providing sufficient active sites. In addition, the presence of oxygen vacancies in Cu/Cu2O can optimize the adsorption kinetics of intermediates in the NRA process and effectively inhibit the formation of by-products. The results show that Cu/CuO2 nanosheet arrays are superior NRA catalysts, achieving a Faradaic efficiency of up to 91.1%, a nitrate conversion of 96.25%, and an NH3 yield rate of 6.11 mg h−1 cm−2. [ABSTRACT FROM AUTHOR]

[Display omitted] Single-atom catalysts (SACs), due to their maximum atomic utilization rate, show tremendous potential for application in the electrocatalytic synthesis of ammonia from nitrate. Yet, the development of superior supports that preserve the high selectivity, activity, and stability of SACs remains an imperative challenge. In this work, based on first-principles calculations and tight-binding (TB) model analysis, a new two-dimensional (2D) carbon nitride monolayer, C 7 N 6 , is proposed. The C 7 N 6 structure exhibits a strong covalent network, with dynamical, thermal, and mechanical stability. Surprisingly, the structural transition from C 9 N 4 to C 7 N 6 corresponds to a semimetallic state transition. Further symmetry analysis unveils that the Dirac states in C 7 N 6 are protected by space–time inversion symmetry, and the physical origin of the Dirac cone was confirmed using the TB model. Additionally, a non-zero Z 2 invariant and significant topological edge states demonstrate its topologically nontrivial nature. Considering the excellent structural and topological properties of C 7 N 6 , a three-step screening strategy is designed to identify eligible SACs for electrochemical nitrate reduction reaction (NO 3 RR), and Ti@C 7 N 6 is identified as possessing the best activity, with the last proton-electron coupling step *NH 2 →*NH 3 being the potential-determining step (PDS), for which the limiting potential is 0.48 V. Moreover, a free energy diagram shows that the *NOH reaction pathway is energetically preferred on Ti@C 7 N 6 , and ab initio molecular dynamics (AIMD) calculations at 500 K confirm its good thermal stability. Our study not only provides excellent CN-based support material but also offers theoretical guidance for constructing highly active and selective SACs for nitrate reduction. [ABSTRACT FROM AUTHOR]

Electrocatalytic reduction of CO2 into high energy‐density fuels and value‐added chemicals under mild conditions can promote the sustainable cycle of carbon and decrease current energy and environmental problems. Constructing electrocatalyst with high activity, selectivity, stability, and low cost is really matter to realize industrial application of electrocatalytic CO2 reduction (ECR). Metal–nitrogen–carbon (M–N–C), especially Ni–N–C, display excellent performance, such as nearly 100% CO selectivity, high current density, outstanding tolerance, etc., which is considered to possess broad application prospects. Based on the current research status, starting from the mechanism of ECR and the existence form of Ni active species, the latest research progress of Ni–N–C electrocatalysts in CO2 electroreduction is systematically summarized. An overview is emphatically interpreted on the regulatory strategies for activity optimization over Ni–N–C, including N coordination modulation, vacancy defects construction, morphology design, surface modification, heteroatom activation, and bimetallic cooperation. Finally, some urgent problems and future prospects on designing Ni–N–C catalysts for ECR are discussed. This review aims to provide the guidance for the design and development of Ni–N–C catalysts with practical application. [ABSTRACT FROM AUTHOR]

Understanding the correlation between the fundamental descriptors and catalytic performance is meaningful to guide the design of high‐performance electrochemical catalysts. However, exploring key factors that affect catalytic performance in the vast catalyst space remains challenging for people. Herein, to accurately identify the factors that affect the performance of N2 reduction, we apply interpretable machine learning (ML) to analyze high‐throughput screening results, which is also suited to other surface reactions in catalysis. To expound on the paradigm, 33 promising catalysts are screened from 168 carbon‐supported candidates, specifically single‐atom catalysts (SACs) supported by a BC3 monolayer (TM@VB/C‐Nn = 0–3‐BC3) via high‐throughput screening. Subsequently, the hybrid sampling method and XGBoost model are selected to classify eligible and non‐eligible catalysts. Through feature interpretation using Shapley Additive Explanations (SHAP) analysis, two crucial features, that is, the number of valence electrons (Nv) and nitrogen substitution (Nn), are screened out. Combining SHAP analysis and electronic structure calculations, the synergistic effect between an active center with low valence electron numbers and reasonable C‐N coordination (a medium fraction of nitrogen substitution) can exhibit high catalytic performance. Finally, six superior catalysts with a limiting potential lower than −0.4 V are predicted. Our workflow offers a rational approach to obtaining key information on catalytic performance from high‐throughput screening results to design efficient catalysts that can be applied to other materials and reactions. [ABSTRACT FROM AUTHOR]