Copper is a promising catalyst for the electroreduction of CO2 (eCO(2)RR). Recently, copper-based single-atom alloys (Cu-SAAs) have been widely used to tune the selectivity of the eCO(2)RR. In experiments, the dominant product can be distinct when different single metal atoms are embedded in Cu, while the fundamental reasons are not clear. In this work, we demonstrated that the thermodynamic investigation of the key intermediates, COOH* and HCOO*, is not sufficient to rationalize the selectivity of Cu-SAAs. We found that the kinetics plays a critical role in selectivity control. The electrochemical barrier calculations and microkinetic simulations indicate that HCOOH is the dominant product on CuPb1 via the COOH* intermediate, beyond the conventional understanding that HCOOH is produced via HCOO*. However, on CuSb1, CO shows higher selectivity than HCOOH due to the lower barrier for associative hydrogenation and dissociation of COOH* to CO* than for HCOOH* production. These simulated results agree well with previous experiments, providing valuable kinetic insights into the selectivity of the eCO(2)RR on Cu-SAAs.

Selective electrooxidation of glycerol (GLY) to glyceric acid (GLA) offers a promising route for GLY valorization but remains hindered by limited activity and stability. Herein, we report a scalable self‐corrosion strategy for large‐area fabrication of a Ru‐doped Pt/NiFe‐LDH catalyst on Ni foam (PtRu/NiFe‐LDH) with an area of up to 36 cm 2 . The incorporation of Ru modulates the electronic structure, enhances the adsorption of both OH − and GLY, and lowers the free energy barrier for OH* formation, thereby significantly boosting catalytic activity to achieve a recorded current density of 439.5 mA cm − 2 . Furthermore, pulse electrolysis effectively suppresses the formation of PtO x , ensuring long‐term stability. When integrated into a GLY oxidation‐assisted hydrogen evolution system, this bifunctional catalyst reduces the cell voltage by 1.01 V relative to conventional water splitting, while delivering 78.5% selectivity towards GLA and stable operation for over 120 h. This work establishes a viable pathway toward the industrialization of selective electrochemical oxidation of GLY to GLA by integrating advanced catalyst design with optimized electrolyzer configuration.

The electrochemical reduction of CO2 (CO2RR) to formic acid (HCOOH) is both economically viable and technically promising for industrial applications. However, current catalysts for HCOOH production exhibit substantial overpotentials to achieve industrial production rates. This limitation stems from the relatively low activity for solvent–water activation of high HCOOH-selective catalysts, e.g., Bi and Sn, which in turn leads to a high energy barrier for the hydrogenation of CO2-to-*HCOO intermediates. Here, we report the exclusive CO2-to-formate conversion on Zn, a well-known CO-selective catalyst with moderate hydrogen evolution activity, via atomic indium oxide domain (In1O6) functionalization. The catalyst demonstrates Faradaic efficiencies for HCOOH exceeding 90

Driven by the goal of global carbon neutrality, electrocatalytic carbon dioxide reduction reaction (eCO2RR) technology has become a research hotspot due to its potential to efficiently convert CO2 into high value-added products, such as ethylene and ethanol. Cu-based catalysts become the core material under their unique electronic structure and C-C coupling ability. It is precisely designed by single atomic sites (SACs) and diatomic site catalysts (DASCs). Combined with the stabilizing effect of composite carriers (such as metal-organic framework (MOF) materials) on the Cu active site, the product selectivity and reaction kinetics were significantly improved. In situ characterization and computational simulation revealed the dynamic reconfiguration of Cu sites and the adsorption mechanism of *CO intermediates. This result confirms that low-coordination Cu sites promote C-C coupling through the Eley-Rideal (ER) pathway, and high-pressure/high-temperature conditions can regulate the reaction path. Despite outstanding laboratory performance, industrial applications still face low stability at high current densities, high-scale preparation costs, and system integration challenges. In the future, it is necessary to focus on the analysis of atomic-level reaction mechanisms, the development of intelligent response materials, and the coupling technology of photoelectric and electrocatalysis, combined with green power matching and carbon tax policy coordination, to promote the leapfrog development of copper-based catalysts from basic research to industrial carbon cycle technology.

The conversion and utilization of carbon dioxide (CO2) is one of the central topics in the energy and environmental research community. The development of electrocatalytic CO2 reduction technology is expected to bring more economic and environmental benefits to the carbon-neutral policy. Although researchers have conducted extensive and in-depth studies on the electrocatalytic CO2 reduction to derive diverse carbonaceous products such as C1 and C2+, the introduction of inorganic nitrogenous molecules in the electrocatalytic CO2 reduction can further expand the production of more valuable C-N bond-containing chemicals, such as amides, amines, and urea. This review focuses on the research progress in the electrochemical C-N coupling of CO2 with diverse nitrogenous small molecules (NH3, N2, NO, NO2−, and NO3−) in aqueous solution. The C-N coupling mechanisms and electrocatalytic performance of catalysts towards different products have been discussed in depth from both computational and experimental aspects. On this basis, the research directions and prospects in this field are proposed, aiming to provide valuable insights into future research on electrocatalytic C-N coupling.

Electrocatalysis is one of the key technologies for developing sustainable and fossil resource free routes to produce fuels and chemicals. The limiting potential (UL), defined by the reaction free energy of the most difficult electrochemical step in a given pathway, is an effective descriptor for establishing the activity trend of a set of electrocatalysts, allowing high throughput screening of new catalysts. However, the reaction network of electrocatalytic processes is rather complex, especially for the reactions with necessary thermochemical steps, e.g., the synthesis of valuable C–N bond-containing chemicals. Thermochemical steps cannot be significantly enhanced by electrode potentials, where kinetics is a non-negligible issue at even high overpotentials. This makes it challenge by using limiting potential to accurately describe activity trends for the reactions with necessary thermochemical steps. To this end, we propose an effective scheme to determine an improved descriptor. We suggest refining the rather complex reaction network at first. In particular, it is suggested to decouple electro- and thermochemical steps and exclude the unfavorable pathways with an excessively high thermochemical barrier. Then, a global comparison among the other pathways can be made, to determine the optimal pathway and the improved descriptor (the reaction free energy of the most difficult step of the optimal pathway, defined as ΔGrRPD-limiting). In addition, the studies on reaction kinetics are also suggested to understand the exception of the best catalysts and provide the direction of experimental optimization. This scheme is of a great compromise between practical efficiency and the accuracy toward the rational design of electrocatalysts.

Electrochemical nitrate reduction(eNO3RR)and nitric oxide reduction(eNORR)to ammonia have emerged as promising and sustainable alternatives to the traditional Haber-Bosch method for am-monia production,particularly within the recently proposed reverse artificial nitrogen cycle route:N2 → NOx → NH3.Notably,experimental studies have demonstrated that eNORR exhibits superior performance over eNO3RR on Cu6Sn5 catalysts.However,the fundamental mechanisms underlying this difference remain poorly understood.Herein,we performed systematic theoretical calculations to explore the reaction pathways,electronic structure effects,and potential-dependent Faradic efficiency associated with ammonia production via these two distinct electrochemical pathways(eNORR and eNO3RR)on Cu6Sn5.By implementing an advanced'adaptive electric field controlled constant potential(EFC-CP)'methodology combined with microkinetic modeling,we successfully reproduced the experimental observations and identified the key factors affecting ammonia pro-duction in both reaction pathways.It was found that eNORR outperforms eNO3RR because it cir-cumvents the *NO2 dissociation and *NO2 desorption steps,leading to distinct surface coverage of key intermediates between the two pathways.Furthermore,the reaction rates were found to exhib-it a pronounced dependence on the surface coverage of *NO in eNORR and *NO2 in eNO3RR.Specifi-cally,the facile desorption of *NO2 on the Cu6Sn5 surface in eNO3RR limits the attainable surface coverage of *NO,thereby impeding its performance.In contrast,the eNORR can maintain a high surface coverage of adsorbed *NO species,contributing to its enhanced ammonia production per-formance.These fundamental insights provide valuable guidance for the rational design of catalysts and the optimization of reaction routes,facilitating the development of more efficient,sustainable,and scalable techniques for ammonia production.

Electrochemical synthesis of chemicals has attracted much research interest in recent years. The rational design of the electrocatalysts is of great importance in improving the reaction activity. To this end, the Reaction Phase Diagram (RPD), with a comprehensive consideration of all possible reaction mechanisms, has offered a valid tool for the thermodynamic evaluation of catalysts. However, facile thermodynamics is merely a prerequisite of high activity, not a sufficient condition. The kinetics should also be considered for further catalyst design, which can be achieved by the method of electric field controlling constant potential (EFC-CP) for electrochemical barrier calculation. In this perspective, we proposed an efficient strategy for electrocatalyst design via general thermodynamic evaluation and specific kinetic study based on the above methods. The application of this strategy in the development of electrocatalysts for NH3 synthesis from NO was also introduced.

Diatomic catalysts (DACs) have recently attracted emerging attention beyond single-atom catalysts (SACs) in achieving targeted catalytic performance, yet their rational design and synthesis remain challenging. Here, we demonstrate the feasibility of designing DACs for highly selective ammonia synthesis from nitrate by developing a water-stable conductive metal-organic framework (cMOF) with a tunable Cu and Ni node (CuxNiy-DBCO) used as a platform catalyst. The well-defined diatomic structure of the cMOFs and adjustable metal components enable systematic identification of active diatomic species and elucidation of the underlying nitrate reduction mechanism. Based on this understanding, we successfully design and synthesize a targeted DACs catalyst (Cu98.5Ni1.5-DBCO) to exhibit unit of selectivity accompanied with ammonia yields of over 200 mg h-1 mgcat-1 (3.5 mmol h-1 cm-2) at a current density of >750 mA cm-2. A Zn-NO3- battery incorporating this optimized DACs as the cathode delivers a power density of 35.6 mW cm-2, highlighting the potential of conductive MOFs in developing target DACs for industrial electrocatalysis.

Although noble metals Ag and Au have similar chemical reactivities, their catalytic selectivity for NO electroreduction is significantly different. Namely, hydroxylamine is often considerably produced on Ag while not observed on the Au electrode. In this study, first-principles calculations and the electric field controlling constant potential (EFC-CP) method are adopted to unveil the underlying reasons. We first reveal a distinct NO* adsorption configuration, vertical on Ag and inclined on Au, leading to different reduction pathways to NOH* and HNO*, respectively. Via complete electrochemical barrier calculations and detailed kinetic analysis, we find the hydroxylamine selectivity difference between Ag and Au is mainly induced by adsorption strength of NH2OH*. On Ag, the obtained NH2OH* prefers to desorb and produce hydroxylamine, while NH2OH* is bonded strongly to Au and favors further reduction to ammonia. The study advances our understanding of factors regulating product selectivity, providing crucial insights for designing NO electroreduction catalysts toward hydroxylamine production.

Earth-abundant, acid-stable catalysts for the oxygen evolution reaction are essential for terawatt-scale hydrogen production using proton exchange membrane (PEM) electrolysers. Here we report that optimizing the lattice oxygen structure of manganese oxide allows it to sustain the oxygen evolution reaction for over one month at 1,000 mA cm −2 in 1 M H 2 SO 4 . The lifetime enhancement was achieved by substituting pyramidal oxygen with planar oxygen, which has a stronger Mn–O bond and thus suppresses the dissolution of manganese ions. Calculations show that the lattice oxygen dissolution is the bottleneck of deactivation, and this process is less favourable by over 0.2 eV on planar oxygen compared with pyramidal oxygen. Our material shows excellent performance even in a PEM electrolyser, reaching 2,000 mA cm −2 at 2 V with durability exceeding 1,000 h at 200 mA cm −2 . This study expands the potential of Earth-abundant catalysts for PEM electrolysis, which may mitigate the reliance on iridium.

Recently, electrochemical coreduction of CO2 and NOx has been proposed as a sustainable route for urea synthesis. Although Zn is the best monometallic catalyst, the urea selectivity on Zn is very low. Toward the rational design of catalysts, the reaction mechanism of urea synthesis was unveiled based on an "electric field controlling constant potential" method, which can directly address the effects of explicit solvent, electric field, and electrode potential on reaction intermediates and transition states. We found that the couplings between CO* and NOH* and CONH* and N* are most favorable for the formation of two C-N bonds of urea, respectively. According to this mechanism, we not only reproduced the experimental Faradaic efficiencies of different products on Zn but also rationalized the activity trend of urea synthesis over a set of catalysts. More interestingly, we have revealed that adsorbed N* species on Fe and Mo have an essential promotion on urea production. Guided by the mechanistic insights, we finally proposed a compressive strain engineering to tune the d-band center of Zn, which can decrease the two C-N coupling barriers to 0.06 and 0 eV, respectively, and deliver a remarkable urea Faradaic efficiency (FE) of 88.5% using CO and NO as reactants.

Ammonia is an important raw material for agricultural production, playing a key role in global food production. However, conventional ammonia synthesis resulted in extensive greenhouse gas emissions and huge energy consumption. Recently, researchers have proposed electrocatalytic reverse artificial nitrogen cycle (eRANC) routes to circumvent these issues, which can be driven by electrocatalysis and sustainable electricity. Here, a theoretical and computational perspective on the challenges and opportunities with the comparison with experimental results: electrochemical reduction of nitrate (eNO3RR) and nitrite (eNO2RR), electrochemical reduction of nitric oxide (eNORR) combined with oxidative nitrogen fixation are presented. By comparison, the N2 -> NO -> NH3 route is proposed as the most promising in case the NO solubility can be solved well in reactor design. Its high efficiency of ammonia production is demonstrated. Instead, the eNO3RR can be another choice because it is non-toxic and the solid-liquid interface is usually efficient for electrochemical reactions, while its low selectivity at low overpotentials is an issue. These fundamentals highlight the potential and key factors of eRANC as an efficient and sustainable route for ammonia production. Ammonia can be synthesized electrochemically via nitrogen oxides as media. This work reviews the electrocatalytic reverse artificial nitrogen cycle (eRANC) as a sustainable route for ammonia synthesis. It compares the electrochemical reduction of nitrate, nitrite, and nitric oxide, emphasizing the potential of the N2 -> NO -> NH3 pathway. It also highlights the importance of improving N2 oxidation pathways to produce NO. image

ABSTRACT A small fraction of NOx (<1%) always exists in CO2 feedstock (e.g. exhausted gas), which can significantly reduce the efficiency of CO2 electroreduction by ∼30%. Hence, electrochemical denitrification is the precondition of CO2 electroreduction. The pH effect is a key factor, and can be used to tune the selectivity between N2 and N2O production in electrochemical denitrification. However, there has been much controversy for many years about the origin of pH dependence in electrocatalysis. To this end, we present a new scheme to accurately model the pH dependence of the electrochemical mechanism. An extremely small pH variation from pH 12.7 to pH 14 can be accurately reproduced for N2O production. More importantly, the obviously different pH dependence of N2 production, compared to N2O, can be attributed to a cascade path. In other words, the N2 was produced from the secondary conversion of the as-produced N2O molecule (the major product), instead of the original reactant NO. This is further supported by more than 35 experiments over varying catalysts (Fe, Ni, Pd, Cu, Co, Pt and Ag), partial pressures (20%, 50% and 100%) and potentials (from −0.2 to 0.2 V vs. reversible hydrogen electrode). All in all, the insights herein overturn long-lasting views in the field of NO electroreduction and suggest that rational design should steer away from catalyst engineering toward reactor optimization.

Electrocatalytic nitrogen oxidation reaction (eN2OR) has emerged as a sustainable strategy for nitrogen fixation. In this work, density functional theory calculations were performed to rationalize the reaction mechanisms, activity, and selectivity of eN2OR on metal dioxides. The anatase (101), anatase (100), and rutile (110) surfaces were investigated to obtain more generalized insights. Based on the reaction phase diagram analysis, the thermochemical mechanisms were identified as most energetically favorable for N2 and *N2O oxidation, and a theoretical activity map was constructed for eN2OR, explaining well the experimental activity trend. Anatase PtO2(100) was screened as the most active catalyst for nitrate production, which could be covered by a monolayer of *OH under the reaction conditions according to the Pourbaix diagram. A method of electric field controlling constant potential was used to calculate the electrochemical barriers on anatase PtO2(100). It was found that the electrochemical barriers of the oxygen evolution reaction will increase with the decrease of potential, while the thermochemical limiting step of the eN2OR is insensitive to potential. Thus, the eN2OR selectivity can be improved by lowering the applied potential. This work unveils fundamental insights into eN2OR and provides a unified understanding to experiments.

Amino acids, e.g. glycine, are vital for lives and the biomedical field, whereas conventional synthesis methods usually have limitations. The electrochemical synthesis of glycine is an emerging route. However, the reaction mechanism and network of glycine electrosynthesis are intricate due to the coexistence of multiple competing (thermochemical and electrochemical) reactions toward different products. Herein, we employed density functional theory calculations to explore the electrosynthesis mechanism of glycine, derived from nitrate and oxalic acid. We initially established a (quasi) activity trend based on global energy optimization and found that Cu-supported Hg-rich sites exhibit great activity toward glycine. The C-N bond of glycine is constructed through the coupling of an amino group (NH2*) and glyoxylic acid (GX) in a local GX-rich environment, independent of oxime production and reduction. We further verified the mechanism using an electric field controlling constant potential method and microkinetic modeling. The computational results aligned well with experimental findings on the potential-dependent selectivity of glycine production. These findings can provide comprehensive insights and potential improvements for glycine electrosynthesis, which is the basis for the development of mercury-free alternative catalysts.

Electrochemical nitrate reduction reaction（eNO 3 RR） has been considered as an alternative route for decentralized ammonia（NH 3 ） synthesis.However,a major challenge is products selectivity at low overpotentials,namely,the competition between nitrite（HNO 2 ） and ammonia.Herein,we employed a single-atom catalyst（FeN 4 ） as model to study the competitive mechanism of NH 3 and HNO 2 by density functional theory calculations.It was found the optimal paths for ammonia and nitrite productions share a key intermediate（NO 2 * ）,whose adsorption structures and preference in the following conversion determines the s electivity.We have incorporated potential-dependent barriers and microkinetic modeling to understand the Faradaic efficiency at different potentials.Our results are in good agreement with the experimental trend of Faradaic efficiencies of NH 3 and HNO 2 ,which can be rationalized well by the charge transfer coefficient（β） for NO 2 * protonation to cisHNO 2 * with respect to that to HNO 2 .A low selectivity of ammonia production at small overpotentials can be ascribed to a kinetic issue.The electron localization function and crystal orbital Hamilton population were analyzed on the initial and transition states for NO 2 protonation to cisHNO 2 * and HNO 2 .The computational mechanistic insights can help to design new catalyst for eNO 3 RR highly active and selective to NH 3 .

Improving both activity and selectivity of C2 oxygenate (C2-oxy) over Rh catalysts is challenging. Experimental results have shown that the C2-oxy yield over pure Rh catalysts can be greatly promoted by the combined effects of alloying (Mn promotor) and confinement. Combining density functional theory calculations and microkinetic simulations, we have revealed that the formed Rh-Mn reaction site breaks the scaling relationship between the adsorption energies of intermediates, resulting in a new CO activation path and the stabilization of C2 intermediates, which can improve not only the CO conversion activity but also the C2-oxy selectivity. On the basis of the alloying effect, the confinement effect can further break the scaling relationship between the adsorption energies of intermediates, which can selectively suppress the formation of some useless but abundant species. This leads to the improved effects for the coverage of key intermediates. As a result, the CO conversion activity is further facilitated without the decrease of C2-oxy selectivity. Therefore, the C2-oxy yield can be enhanced. However, without the Mn promotor, the confinement effect alone can only slightly improve the CO conversion activity with poor C2-oxy selectivity. The insights herein regarding the synergistic effects with alloying and confinement are of great significance to regulate the activity and selectivity of C2-oxy in syngas conversion.

The removal of nitric oxide is an important environmental issue, as well as a necessary prerequisite for achieving high efficiency of CO 2 electroreduction. To this end, the electrocatalytic denitrification is a sustainable route. Herein, we employ reaction phase diagram to analyze the evolution of reaction mechanisms over varying catalysts and study the potential/pH effects over Pd and Cu. We find the low N 2 selectivity compared to N 2 O production, consistent with a set of experiments, is limited fundamentally by two factors. The N 2 OH* binding is relatively weak over transition metals, resulting in the low rate of as-produced N 2 O* protonation. The strong correlation of OH* and O* binding energies limits the route of N 2 O* dissociation. Although the experimental conditions of varying potential, pH and NO pressures can tune the selectivity slightly, which are insufficient to promote N 2 selectivity beyond N 2 O and NH 3 . A possible solution is to design catalysts with exceptions to break the scaling characters of energies. Alternatively, we propose a reverse route with the target of decentralized ammonia synthesis.