High Faraday Efficiency Research Articles

Surmounting scaling relationship on Cu-base diatomic catalysts by geminal-site-induced synergistic effect for high-selectivity CO2 electrochemical reduction to CO

Cu-based nanomaterials are regarded as the most promising alternatives for catalyzing electrochemical CO2 reduction reactions (ECO2RR). However, its development is impeded by the low selectivity. Improving the selectivity of ECO2RR plays a key role in the commercialized progress of Cu-based nanomaterials. Herein, we screened out the most potential diatomic site from representative Cu-based diatomic catalysts (DACs) and their responsive single-atomic catalysts through theoretical calculations and experiments. The theoretical calculations revealed that the synergistic effect between the diatomic sites in Cu-Mn and Cu-Fe DACs can assist them to break through the limit of scaling relationship and realize the high-selectivity ECO2RR to CO. This was verified by the electrochemical measurements that the as-synthesized nitrogen-doped carbon-supported Cu-Mn and Cu-Fe DACs (Cu-Mn/NC and Cu-Fe/NC) delivered high Faraday efficiency of CO (FECO >90%) at a wide potential range. Furthermore, the Cu-Mn/NC displayed remarkable mass activity of 1760 A g‒1, which is about 27.3 times of a Cu single-atom catalyst, and catalytic stability that goes through a 30-hour electrolytic process without current attenuation at ‒0.6 V. Our work suggests that this synergistic effect can be used as a viable and general strategy to design DACs with high-selectivity ECO2RR for desired products.

Cu-Bi Bimetallic Catalysts Derived from Metal-Organic Framework Arrays on Copper Foam for Efficient Glycine Electrosynthesis.

Glycine as one of the most abundant amino acids in human proteins, with extensive applications in both life and industry, is conventionally synthesized through complex procedures or toxic feedstocks. In this study, we present a facile and benign electrochemical pathway for synthesis of glycine through reductive coupling of glyoxylic acid and nitrate over a copper-bismuth bimetal catalyst derived from a metal-organic framework (MOF) array on copper foam (Cu/Bi-C@CF). Remarkably, Cu/Bi-C@CF achieves a fantastic selectivity of 89 %, corresponding a high Faraday efficiency of 65.9 %. From control experiments, the introduction of Bi caused the binding energy of Cu shift to a lower state, which leads to a high selectivity towards the formation of key intermediate hydroxylamine rather than ammonia product, facilitating the formation of oxime and providing additional sites for subsequent hydrogenation reaction on the way to glycine. Moreover, the derivation of MOF arrays ensures the effective dispersion of Bi and enhances the stability of Cu/Bi-C@CF. This innovative approach not only presents sustainable pathways for the production of value-added organonitrogen compounds utilizing readily available carbon and nitrogen sources, but also provides novel insights into the design of multistage structural catalysts for sequential reactions.

Cu−Bi Bimetallic Catalysts Derived from Metal–Organic Framework Arrays on Copper Foam for Efficient Glycine Electrosynthesis

AbstractGlycine as one of the most abundant amino acids in human proteins, with extensive applications in both life and industry, is conventionally synthesized through complex procedures or toxic feedstocks. In this study, we present a facile and benign electrochemical pathway for synthesis of glycine through reductive coupling of glyoxylic acid and nitrate over a copper‐bismuth bimetal catalyst derived from a metal–organic framework (MOF) array on copper foam (Cu/Bi−C@CF). Remarkably, Cu/Bi−C@CF achieves a fantastic selectivity of 89 %, corresponding a high Faraday efficiency of 65.9 %. From control experiments, the introduction of Bi caused the binding energy of Cu shift to a lower state, which leads to a high selectivity towards the formation of key intermediate hydroxylamine rather than ammonia product, facilitating the formation of oxime and providing additional sites for subsequent hydrogenation reaction on the way to glycine. Moreover, the derivation of MOF arrays ensures the effective dispersion of Bi and enhances the stability of Cu/Bi−C@CF. This innovative approach not only presents sustainable pathways for the production of value‐added organonitrogen compounds utilizing readily available carbon and nitrogen sources, but also provides novel insights into the design of multistage structural catalysts for sequential reactions.

Preparation of NiCo hydroxide by chloride corrosion for electrocatalytic upcycling of polyethylene terephthalate plastic waste

Upcycling plastic waste into value-added chemicals is an innovative strategy that addresses environmental concerns and creates economic value. As one of the polyesters that is widely used, polyethylene terephthalate (PET) plastic waste is employed as the model substrate. Here we report a chloride corrosion method to synthesize bimetallic hydroxide catalysts on nickel foam. By using a nickel–cobalt hydroxide catalyst (NiCo-OH/NF), we demonstrate an electrocatalytic oxidation strategy to transform real-world polyethylene terephthalate (PET) water bottle into potassium formate and terephthalic acid (TPA) with high Faraday efficiency of 92.1 % at 1.40 V vs. RHE. The in situ spectroscopy and theoretical calculations provide insights into the catalytic mechanism especially active sites, pivotal intermediates, and favorable pathways. This work highlights the significant potential of electrochemical conversion as a means of achieving PET upcycling.

Trace Cu-Induced Low C─N Coupling Barrier on Amorphous Co Metallene Boride for Boosting Electrochemical Urea Production.

The electrochemical C─N coupling of carbon dioxide (CO2)and nitrate(NO3 -)is an alternative strategy to the traditional high-energy industrial pathway for urea synthesis, which urgently requires the design of efficient catalysts to achieve high yield and Faraday efficiency (FE). Here, amorphous low-content copper-doped cobalt metallene boride (a-Cu0.1CoBx metallene) is designed for urea synthesis via electrochemical C─N coupling. The a-Cu0.1CoBx metallene can drive electrocatalytic C─N coupling of CO2 and NO3 - for urea synthesis in CO2-saturated 0.1m KNO3 electrolyte, with 27.7% of FE and 312µgh-1mg-1 cat. of yield at -0.5V, as well as superior cycling stability. The in situ Fourier transform infrared and theoretical calculations reveal that electronic effect between Cu, Co, and B causes Cu and Co as dual active sites to promote the adsorption of reactants. Furthermore, the introduced trace Cu reduces the reaction energy barrier of the C─N coupling to facilitate urea synthesis. This work provides a promising route for the optimization of Co-based metallene for the electrosynthesis of urea through C─N coupling.

Boron-Doping Engineering in AgCd Bimetallic Catalyst Enabling Efficient CO2 Electroreduction to CO and Aqueous Zn-CO2 Batteries.

The limited adsorption and activation of CO2 on catalyst and the high energy barrier for intermediate formation hinder the development of electrochemical CO2 reduction reactions (CO2RR). Herein, this work reports a boron (B) doping engineering in AgCd bimetals to alleviate the above limitations for efficient CO2 electroreduction to CO and aqueous Zn-CO2 batteries. Specifically, the B-doped AgCd bimetallic catalyst (AgCd-B) is prepared via a simple reduction reaction at room temperature. A combination of in situ experiments and density functional theory (DFT) calculations demonstrates that B-doping simultaneously enhances the adsorption and activation of CO2 and reduces the binding energy of the intermediates by moderating the electronic structure of bimetals. As a result, the AgCd-B catalyst exhibits a high CO Faraday efficiency (FECO) of 99% at -0.8V versus reversible hydrogen electrode (RHE). Additionally, it maintains a FECO over 92% at a wide potential window of 600mV (-0.6 to -1.1V versus RHE). Furthermore, the AgCd-B catalyst coupled with the Zn anode to assemble aqueous Zn-CO2 batteries shows a power density of 20.18mW cm-2 and a recharge time of 33h.

Customizing Ionic Liquids Functionalized MOFs Composites with Hydrophobic Interface for Electrochemical CO2 Reduction.

The electrochemical carbon dioxide reduction reaction (CO2RR) to generate feedstocks for chemical products (e.g., carbon monoxide, CO) offers a highly attractive method for achieving the closure of the carbon cycle. Ionic liquids (ILs)-functionalized Cu-based catalyst Cu2O-HKUST-1/IL1/PTFE was developed, configuring metal-organic frameworks(MOFs) based materials with high adsorption and multiple active sites. The modified electrocatalysts exhibited high specific surface area, strong CO2 adsorption capacity, abundant active sites, and fast charge transfer rate. The nucleophilic active site of deprotonation at the C2 site in imidazole ILs further improved the selectivity of proton migration and CO product generation, which was verified through DFT calculations for the low Gibbs free energy of the generated intermediate interactions. In addition, the hydrophobic interface constructed by PTFE facilitated the inhibition of the hydrogen evolution reaction (HER) and significantly improved the efficiency of CO2 electroreduction. The Cu2O-HKUST-1/IL1/PTFE catalyst manifested a high C1 Faraday efficiency (FE) up to 96.5% and in particular 92.7% for FECO at -1.7 V vs RHE. The present work provides an efficient strategy for configuring ILs-functionalized MOFs-based materials with good hydrophobic interfaces to enhance the efficiency of CO2 electroreduction to C1 products.

ZIF-8-derived carbon substrates embedded with atomically dispersed FeN2O2 active sites as bifunctional catalysts for electrochemical carbon dioxide and oxygen reduction

Transition metal assemblies on nitrogen-containing carbon substrates have promising applications as bifunctional electrocatalysts for electrochemical carbon dioxide reduction reaction (CO2RR) and oxygen reduction reaction (ORR). In this study, ZIF-8 with a rhombic dodecahedral morphology was grown from zinc nitrate and 2-methylimidazole feedstock. Then, a nitrogen-containing carbon substrate with a pore structure was formed after the release of Zn through high-temperature calcination. During the calcination process at 700°C, Fe atoms were physically adsorbed on the nitrogen-containing carbon substrate and ligated with N/O to form FeN2O2 reactive sites. For CO2RR, FeN2O2/NC exhibited excellent catalytic properties for converting CO2 to CO, achieving a high Faraday efficiency of 95.5 % at −0.7 V. Under alkaline conditions, it demonstrated ORR performance (E1/2 = 0.83 V) comparable with that of Pt/C (E1/2 = 0.82 V). This study not only presents an energy-efficient method for CO2RR but also provides new insights into highly active catalysts for ORR.

Electron-deficient CoO induced charge redistribution on CuCoO-NC nanohybrid for electrocatalytic reduction of nitrate to ammonia

The use of electrochemical tactics to reduce nitrate to the valorized product ammonia has become the hot topic. Recently, the synergistic effect of metal/metal oxide is provided to significantly enhance the electrocatalytic performance of nitrate reduction as opposed to monometallic catalyst. In this work, a reticulated fibre structure with Cu/CoO nanoparticles (CuxCoyO-NC) was prepared for electrocatalytic nitrate reduction (NO3-RR) to ammonia. The optimized catalyst (Cu1Co1O-NC) displayed brilliant performance for NO3-RR with high Faraday efficiency (FE) of 97.9 %, the excellent NH3 yield rate of 0.45 mmol h−1 cm−2, prominent NH3 selectivity of 98.4 % and efficient NO3– conversion of 99.2 % at −0.79 V vs reversible hydrogen electrode (RHE). Besides, Cu1Co1O-NC also exhibits the potential for uranium recovery from simulated wastewater containing nitrate and uranyl ions with a total yield of 508 mg ammonium diuranate after i-t measurement for 6 times. This work not only provides an efficient catalyst for reduction nitrate but also proposes the sustainable method for uranium containing sewage realizing nitrogen cycle.

Unbiased Photoelectrochemical H2O2 Coupled to H2 Production via Dual Sb2S3‐Based Photoelectrodes with Ultralow Onset Potential

AbstractThe productions of hydrogen peroxide (H2O2) and hydrogen (H2) in a photoelectrochemical (PEC) water splitting cell suffer from an onset potential that limits solar conversion efficiencies. Moreover, the formation of H2O2 through two‐electron PEC water oxidation reaction competes with four‐electron oxidation evolution reaction. Herein, we developed the surface selenium doped antimony trisulfide photoelectrode with the integrated ruthenium cocatalyst (Ru/Sb2(S,Se)3) to achieve the low onset potential and high Faraday efficiency (FE) for selective H2O2 production. The photoanode exhibits an outstanding average FE of 85 % in the potential range of 0.4–1.6 VRHE and the H2O2 yield of 1.01 μmol cm−2 min−1 at 1.6 VRHE, especially at low potentials of 0.1–0.55 VRHE with 80.4 % FE. Impressively, an unassisted PEC system that employs light and electrolyte was constructed to simultaneously produce H2O2 and H2 production on both the Ru/Sb2(S,Se)3 photoanode and the Pt/TiO2/Sb2S3 photocathode. The integrated system enables the average PEC H2O2 production rate of 0.637 μmol cm−2 min−1 without applying any addition bias. To our knowledge, this is the first demonstration that Sb2S3‐based photoelectrodes exhibit H2O2/H2 two‐side production with a strict key factor of the system, which represents its powerful platform to achieve high efficiency and productivity and the feasibility to facilitate value‐added products in neutral conditions.

In-situ exsolved Ni nanoparticles for boosting CO2 reduction in solid oxide electrolysis cell

Due to their excellent high Faraday efficiency, perovskite solid oxide cells (SOECs) have attracted considerable attention. Nevertheless, they still face significant challenges in terms of stability and electrocatalytic activity during CO₂ electrolysis. In this study, Ni particles in La0.65Ba0.35Mn1-xNixO3-δ are successfully separated by a unique in-situ exsolved method of metal nanoparticles, which are uniformly anchored to the electrode surface as Ni nanometal particles. This effectively suppresses the generation of carbon deposits on the cathode surface. Under test conditions of 850 °C, 1.6 V and 50 sccm flow rate, the CO yield of the modified cathode material reached 5.9 mL min−1 cm−2, which is nearly four times higher than that before doping. The synergistic effect of in-situ exsolution of Ni metal nanoparticles with oxygen defects generated by the perovskite, creating more active locations for CO2 adsorption and electrolysis, is responsible for the significant improvement in electrochemical performance. This work provides new strategies and ideas for the development of efficient and durable SOEC cathode materials.

Unbiased Photoelectrochemical H2O2 Coupled to H2 Production via Dual Sb2S3-Based Photoelectrodes with Ultralow Onset Potential.

The productions of hydrogen peroxide (H2O2) and hydrogen (H2) in a photoelectrochemical (PEC) water splitting cell suffer from an onset potential that limits solar conversion efficiencies. Moreover, the formation of H2O2 through two-electron PEC water oxidation reaction competes with four-electron oxidation evolution reaction. Herein, we developed the surface selenium doped antimony trisulfide photoelectrode with the integrated ruthenium cocatalyst (Ru/Sb2(S,Se)3) to achieve the low onset potential and high Faraday efficiency (FE) for selective H2O2 production. The photoanode exhibits an outstanding average FE of 85 % in the potential range of 0.4-1.6 VRHE and the H2O2 yield of 1.01 μmol cm-2 min-1 at 1.6 VRHE, especially at low potentials of 0.1-0.55 VRHE with 80.4 % FE. Impressively, an unassisted PEC system that employs light and electrolyte was constructed to simultaneously produce H2O2 and H2 production on both the Ru/Sb2(S,Se)3 photoanode and the Pt/TiO2/Sb2S3 photocathode. The integrated system enables the average PEC H2O2 production rate of 0.637 μmol cm-2 min-1 without applying any addition bias. To our knowledge, this is the first demonstration that Sb2S3-based photoelectrodes exhibit H2O2/H2 two-side production with a strict key factor of the system, which represents its powerful platform to achieve high efficiency and productivity and the feasibility to facilitate value-added products in neutral conditions.

Spatial Structure of Electron Interactions in High-entropy Oxide Nanoparticles for Active Electrocatalysis of Carbon Dioxide Reduction.

High-entropy oxides (HEOs) exhibit distinctive catalytic properties owing to their diverse elemental compositions, garnering considerable attention across various applications. However, the preparation of HEO nanoparticles with different spatial structures remains challenging due to their inherent structural instability. Herein, ultrasmall high-entropy oxide nanoparticles (less than 5nm) with different spatial structures are synthesized on carbon supports via the rapid thermal shock treatment. The low-symmetry HEO, BiSbInCdSn-O4, demonstrates exceptional performance for electrocatalytic carbon dioxide reaction (eCO2RR), including a lower overpotential, high Faraday efficiency across a wide electrochemical range (-0.3 to -1.6V), and sustained stability for over100h. In the membrane electrode assembly electrolyzer, BiSbInCdSn-O4 achieves a current density of 350mAcm-2 while maintaining good stability for 24h. Both experimental observations and theoretical calculations reveal that the electron donor-acceptor interactions between bismuth and indium sites in BiSbInCdSn-O4 enable the electron delocalization to facilitate the efficient adsorption of CO2 and hydrogenation reactions. Thus, the energy barrier of the rate-determining step is reduced to enhance the electrocatalytic activity and stability. This study elucidates that the spatial structure of metal sites in HEOs is able to regulate CO2 adsorption status for eCO2RR, paving the way for the rational design of efficient HEO catalysts.

Regulation of surface oxygen vacancy of Cu-CeO2/TiO2 heterostructures via fast Joule heating method for enhanced CO2 electrochemical reduction

Strict control of carbon emissions is crucial for expediting the achievement of carbon neutrality. However, the current CO2RR electrocatalytic exhibits numerous shortcomings that impede the enhancement of catalytic activity. Issues such as lengthy catalyst preparation times, and high levels of precious metal content. Additionally, the aggregation of ultrafine nanoparticles contributes to a rapid deterioration in catalytic performance. Herein, a Joule-heating method is efficiently utilized to synthesize heterostructures nano-catalysts for CO2 electroreduction on carbon cloth substrates. This method takes advantage of the thermoelectric coupling of the carbon cloth to achieve carbothermal reduction, while also regulating phase composition and introduction of oxygen vacancies. The Cu-CeO2/TiO2/CC catalyst synthesized in this method showed a current density in CO2 of −32 mA·cm−2 at −1.0 V (vs. RHE). Notably, this catalyst demonstrated high CO selectivity and Faraday efficiency (FECO) of up to 82.5 % at a low potential of −0.3 V (vs. RHE). Optimal electrochemical performance is achieved at a power of 40 W. The ultra-fast temperature change process prevented the agglomeration of catalyst particles and facilitated the construction of a stable heterogeneous interface with a high oxygen vacancy concentration. In conclusion, this study presents a promising approach, particularly for the rapid preparation of low-cost, highly selective non-precious metal electrocatalysts.

Enhanced electron transfer kinetics via constructing co-catalytic system of cerium oxide and carbon dots enabling efficient electrosynthesis of hydrogen peroxide in neutral media

The sluggish kinetics coupled with the competition of four-electron pathway in neutral media diminishes the production efficiency of hydrogen peroxide (H2O2) via the two-electron oxygen reduction reaction (2e− ORR). To address this dilemma, this contribution proposes one electron modulation strategy to expedite the charge transfer capability by integrating carbon dots with CeO2 (CDs/CeO2) for the efficient neutral electrosynthesis of H2O2. It was found that the integration could effectively bolster both the activity and selectivity of 2e− ORR on CDs and CeO2. Remarkably, the highest 2e− selectivity could reach up to 92 % for the optimized CDs/CeO2, substantially surpassing that (77 %) of pristine CeO2, together with about 1.5 times enhancement of activity. Meanwhile, it also delivered a superior long durability at 20 mA cm−2 for 24 h and a high Faraday efficiency of 97 %. Further in-situ transient potential scanning (TPS) technique revealed that the pseudo-capacitance and charge storage capacity of CeO2 were significantly tuned by CDs during dynamic ORR process, being conducive to the reaction kinetics and the 2e− selectivity. The findings in this work not only extends the co-catalytic system based on CDs and rare earth materials for 2e− ORR, but also offers novel insights into correlation between their electron distribution dynamics and 2e− ORR performance.

Recent Advancements in Materials for Proton-Conducting Reversible Solid Oxide Cells

The escalating threats posed by climate change and environmental issues underscore the need for urgent exploration of clean energy technologies. In this context, proton-conducting reversible solid oxide cells (P-RSOCs) have emerged as promising contenders for large-scale energy storage and conversion. Their efficacy at intermediate temperatures (400 - 600 °C) is a distinctive advantage, attributed to the remarkable ionic conductivity of proton conductors within this temperature range. This feature positions P-RSOCs favorably for the efficient, cost-effective, and enduring conversion between clean electricity and green hydrogen.However, the successful commercialization of P-RSOCs hinges on the rational design of novel materials and meticulous surface/interface modifications to significantly enhance performance and durability. Achieving prolonged durability during cycling between fuel cell and electrolysis modes while maintaining high Faraday efficiency and roundtrip energy efficiency is of paramount importance. A central challenge involves the development of electrolyte materials exhibiting exceptional stability and a high ionic transference number under operating conditions. Additionally, bifunctional electrodes/catalysts, particularly for the oxygen electrode, must demonstrate elevated activity for efficient dual-mode operation.To effectively tackle these challenges, it is imperative to devise new protocols for controlling the structure, composition, and morphology of materials across multiple length scales. Equally crucial is gaining a fundamental understanding of degradation mechanisms and electrode processes. This presentation will illuminate the critical scientific challenges inherent in developing a new generation of P-RSOCs, providing insights into the latest advancements in electrolyte materials and bifunctional electrodes/catalysts. Furthermore, it will highlight strategies for enhancing durability and electrode activity through surface/interface modification, along with the latest developments in modeling, simulation, and in situ characterization techniques to deepen our understanding of the underlying mechanisms. The presentation will conclude prospects for achieving low-cost, highly efficient, and durable P-RSOCs through innovative material-based solutions.

Gradient-concentration RuCo electrocatalyst for efficient and stable electroreduction of nitrate into ammonia

Electrocatalytic nitrate reduction to ammonia holds great promise for developing green technologies for electrochemical ammonia energy conversion and storage. Considering that real nitrate resources often exhibit low concentrations, it is challenging to achieve high activity in low-concentration nitrate solutions due to the competing reaction of the hydrogen evolution reaction, let alone considering the catalyst lifetime. Herein, we present a high nitrate reduction performance electrocatalyst based on a Co nanosheet structure with a gradient dispersion of Ru, which yields a high NH3 Faraday efficiency of over 93% at an industrially relevant NH3 current density of 1.0 A/cm2 in 2000 ppm NO3- electrolyte, while maintaining good stability for 720 h under −300 mA/cm2. The electrocatalyst maintains high activity even in 62 ppm NO3- electrolyte. Electrochemical studies, density functional theory, electrochemical in situ Raman, and Fourier-transformed infrared spectroscopy confirm that the gradient concentration design of the catalyst reduces the reaction energy barrier to improve its activity and suppresses the catalyst evolution caused by the expansion of the Co lattice to enhance its stability. The gradient-driven design in this work provides a direction for improving the performance of electrocatalytic nitrate reduction to ammonia.

Understanding electron structure of covalent triazine framework embraced with gold nanoparticles for nitrogen reduction to ammonia

Regulating the electron structure and precise loading sites of metal-active sites within the highly conjugated and porous covalent-triazine frameworks (CTFs) is essential to promoting the nitrogen reduction reaction (NRR) performance for electrocatalytic ammonia (NH3) synthesis under ambient conditions. Herein, experimental method and density functional theory (DFT) calculations were conducted to deeply probe the effect on NRR of the modulation of modulating the electron structure and the loading site of gold nanoparticles (Au NPs) in a two-dimensional (2D) CTF. 2D CTF synthesized using melem and hexaketocyclohexane octahydrate as building blocks (denoted as M−HCO−CTF) served as a robust scaffold for loading Au NPs to form an M−HCO−CTF@AuNP hybrid. DFT results uncovered that well-defined Au sites with tunable local structure were the active site for driving the NRR, which can significantly suppress the conversion of H+ into *H adsorption and enhance the nitrogen (N2) adsorption/activation. The overlapped Au (3d) and *N2 (2p) orbitals lowered the free energy of the rate-determining step to form *NNH, thereby accelerating the NRR. The M−HCO−CTF@AuNPs electrocatalyst exhibited a large NH3 yield rate of 66.3 μg h−1 mg−1cat. and a high Faraday efficiency of 31.4 % at − 0.2 V versus reversible hydrogen electrode in 0.1 M HCl, superior to most reported CTF-based ones. This work can provide deep insights into the modulation of the electron structure of metal atoms within a porous organic framework for artificial NH3 synthesis through NRR.

Nitrogen‐Doped Carbon‐Encapsulated Nickel Nanoparticle Catalysts Using Covalent Organic Frameworks as Templates for Electrochemical CO2 Conversion

AbstractElectrochemical CO2 reduction (ECR) reactions, powered by cleaner energy, possess significant promise in mitigating CO2 emissions and achieving carbon recycling. Herein, Ni@N‐C electrocatalysts with encapsulated structures are prepared using covalent organic frameworks (COFs) as templates, where COF‐derived nitrogen‐doped carbon (N‐C) is utilized to wrap Ni nanoparticles. At the potential of −0.97 V vs. RHE, 2Ni@N‐C‐800 is characterized by a high current density (j = 24.2 mA cm‐2) and relatively high CO Faraday efficiency (FECO = 72%), reflecting its good catalytic activity. The ECR performance of 2Ni@N‐C‐800 is due to the cooperative interaction between Ni nanoparticles and the N‐C structure, which is inferred from control and poisoning measurements. This study provides a new idea for finding efficient and stable ECR catalysts.

Sulfur-Bridged Asymmetric CuNi Bimetallic Atom Sites for CO2 Reduction with High Efficiency.

Double-atom catalysts (DACs) with asymmetric coordination are crucial for enhancing the benefits of electrochemical carbon dioxide reduction and advancing sustainable development, however, the rational design of DACs is still challenging. Herein, this work synthesizes atomically dispersed catalysts with novel sulfur-bridged Cu-S-Ni sites (named Cu-S-Ni/SNC), utilizing biomass wool keratin as precursor. The plentiful disulfide bonds in wool keratin overcome the limitations of traditional gas-phase S ligand etching process and enable the one-step formation of S-bridged sites. X-ray absorption spectroscopy (XAS) confirms the existence of bimetallic sites with N2Cu-S-NiN2 moiety. In H-cell, Cu-S-Ni/SNC shows high CO Faraday efficiency of 98.1% at -0.65V versus RHE. Benefiting from the charge tuning effect between the metal site and bridged sulfur atoms, a large current density of 550mAcm-2 can be achieved at -1.00V in flow cell. Additionally, in situ XAS, attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS), and density functional theory (DFT) calculations show Cu as the main adsorption site is dual-regulated by Ni and S atoms, which enhances CO2 activation and accelerates the formation of *COOH intermediates. This kind of asymmetric bimetallic atom catalysts may open new pathways for precision preparation and performance regulation of atomic materials toward energy applications.