CO2 Reduction Research Articles

Engineering Co Single Atoms in Ultrathin BiOCl Nanosheets for Boosted CO2 Photoreduction

AbstractDespite the development of a range of photocatalysts for CO2 reduction, the practical applications are significantly limited by low conversion efficiencies and their reliance on sacrificial agents, which are rooted in thermodynamic and kinetic challenges related to CO2 conversion. Here, the engineering of Co single atoms in ultrathin single‐crystal BiOCl nanosheets for boosted photocatalytic CO2 reduction is reported. The engineering of Co atoms modulates the distribution of photogenerated charges at the catalyst surface, controlling key surface reaction dynamics and suppressing surface electron‐hole recombination. This modulation also improves light absorption and enhances CO2 adsorption and activation, leading to more efficient surface reactions. Notably, CO2 is stably adsorbed onto the (001) face of BiOCl through a Bi‐O‐C(= O)‐Co‐O coordination unit, which lowers the activation energy for CO2 reduction and reduces the formation energy of COOH− intermediates. As a result, the BiOCl photocatalysts achieve a CO formation rate of 183.9 µmol g−1 h−1, when irradiated with a 300 W Xe lamp without cocatalysts or sacrificial agents. It represents an ≈13‐fold increase compared to that of pristine BiOCl, and surpasses most reported Bi‐based photocatalysts to date. Current work provides valuable insights into engineering of single atoms for developing advanced CO2‐reduction photocatalysts.

A Well‐Advanced High‐Throughput Test System for Electrocatalytic Screening Applications Under Industrial Relevant Conditions – A Perspective to Accelerate Electrolysis Research and Development

ABSTRACTElectrolysis is a dynamic research area in which both mature and new promising processes, such as alkaline water electrolysis and electrochemical CO2 reduction, are under enormous development pressure due to their high relevance for the energy sector. High‐throughput (HT) technologies are efficient screening platforms that can accelerate research activities and significantly shorten development times. Over the past 25 years, various HT platforms have found their way into electrochemical research. These typically have one or more major disadvantages: they are characterized by abstract experimental conditions, designed for a specific application or process, or generate insufficiently comparable data. In this publication, we present a newly developed HT test system that enables the parallel operation of 16 electrochemical bench‐scale flow cells under industry‐relevant test conditions. The specially developed modular flow cell can be operated variably in the fully automated system and allows research into the most common applications in electrochemistry for many different processes with a focus on all relevant variants of water electrolysis and electrochemical CO2 reduction. Both the HT system and the developed flow cell are designed to accelerate the generation of reliably reproducible data with high comparability in order to strengthen scientific exchange. The fully automated process control, online analysis and programmable feedback loops of the HT test system provide great potential for the design of experiment strategies. The implementation of Design of Experiment strategies will maximize the testing efficiency of this innovative research system.

Improvement of Photocatalytic CO2 Reduction with Conjugated Organic Polymers by Rational Modulation of Donor, Acceptor and Bonding Method.

The use of metal-free catalysts to convert CO2 into valuable chemicals is very challenging. Here, we synthesized a conjugated organic polymer (TpTf-1) featuring 2,4,6-Triphenyl-1,3,5-Triazine as the acceptor unit, triphenylamine as the donor unit, and vinylidene bond as the linkage. The local structure of donor-acceptor (D-A) forms an intramolecular electric field that can promote the separation of photogenerated electrons and charges, meanwhile, the vinylidene bond can further change the charge distribution to promote exciton dissociation. Without the use of photosensitizers, the TpTf-1 exhibits outstanding selectivity of CO of up to 91.96 %, with a production rate of 45.2 μmol g-1 h-1 at visible light, which is 3.4-fold than TaTf-1 with the same D-A structure but linking in imine bond and is 2.8-fold than TpTf-2 linking in vinylidene bond but with a different donor unit. Moreover, TpTf-1 has a CO production rate of up to 117.3 μmol g-1 h-1 under full wavelength light irradiation.

Experimental and calculation investigations of the photocatalytic selective and performance for CO2 reduction by cobalt-doped Bi4O5Br2 nanosheets

This study delves into the photocatalytic process of an innovative Co-doped Bi4O5Br2 material synthesized through a straightforward process. Experimental and theoretical findings corroborate that cobalt doping remarkably enhances the CO2 reduction capability of Bi4O5Br2 catalysts under visible light. Findings indicate that Co-doped Bi4O5Br2 exhibits substantial advantages over its pristine counterpart in photocatalytic CO2 reduction. Notably, the catalyst with 4 at.% Co doping demonstrates the highest photocatalytic CO2 reduction efficiency, achieving CO and methane production activities of up to 9.46 and 0.20 μmol/g/h, respectively. Furthermore, the low activation energy for CO2 reduction in Co-doped Bi4O5Br2, as indicated by reaction pathways calculations, facilitates the process. Detailed experimental results reveal that Co incorporation does not alter the surface morphology or the crystalline phase of the photocatalyst. The superior efficiency of Co-doped Bi4O5Br2 is attributed to multiple factors: a narrow band gap, expanded visible light absorption spectrum, greater absorption intensity within the visible range, and enhanced separation efficiency of photogenerated electrons and holes compared to pristine Bi4O5Br2. This highlights the practical application of Co-doped Bi4O5Br2 for enhancing photocatalytic performance, supporting future advancements in solar energy utilization and the creation of high-value chemical products.

In situ construction of S-scheme heterojunctions between BiOCl and Bi-MOF for enhanced photocatalytic CO2 reduction and pollutant degradation

Recently, photocatalytic technology has been widely used as a sustainable method to address environmental pollution issues. Herein, BiOCl/Bi-MOF (BOC/Bi-MOF) based semiconductor photocatalysts with S-scheme heterojunction were fabricated by an in situ growth method, and the photocatalytic activity of the materials was explored for CO2 reduction and pollutant degradation. As confirmed by density functional theory calculations and physiochemical characterizations, the established S-scheme heterojunction confers enhanced carrier separation efficiency and retention of redox capability to the BOC/Bi-MOF. Through an improved combination of charge separation and surface reactions, the prepared BOC/Bi-MOF efficiently reduces CO2 solely to CO. The heterojunction as catalyst is more durable and effective than any of its single component. The CO evolution rate of the optimized composite catalyst was 7.66 and 33.10 times of those of BiOCl and Bi-MOF, respectively. In addition, BOC/Bi-MOF exhibits a high efficiency in the photocatalytic degradation of the pollutant rhodamine B (RhB) in aqueous environments, and the pollutant was completely removed within 20 min. Due to the generation of interfacial potential differences, the internal electric field (IEF) generation at heterogeneous interfaces facilitates the separation and transfer of photogenic charges. This work demonstrated a practical and effective route for in situ growth of S-scheme heterojunctions with high efficiencies in CO2 reduction and RhB degradation.

Tandem Gold/Copper Catalysis and Morphological Tuning via Wrinkling to Boost CO2 Electroreduction into C2+ Products

Powered by renewable electricity, electrochemical CO2 reduction (CO2R) offers a sustainable route for the production of fuels and chemicals that are traditionally produced from fossil fuels. However, designing and developing an efficient electrocatalyst for CO2-to-C2+ product conversion remains challenging. Here, a gold-copper tandem catalyst electrode design is introduced that leverages the structural effects of a wrinkled morphology to improve the CO2R selectivity and activity in a three-electrode electrochemical cell. The wrinkled electrode structure significantly increases the electrochemical active surface area, resulting in enhanced CO2R current density for both the singular wrinkled gold and wrinkled copper electrodes. Specifically, there is a 130% increase in partial current density towards CO for a wrinkled gold electrode versus planar gold electrode at -0.7V versus the reversible hydrogen electrode (VRHE), and a 50% increase in partial current density for C2+ products for a wrinkled copper electrode at -1.05 VRHE compared to a planar copper electrode. A wrinkled gold-copper tandem electrode further enhances the partial current density of C2+ products by an additional 60% beyond that of the wrinkled copper electrode (at -1.05 VRHE), illustrating the synergistic effect of the three-dimensional wrinkled morphology combined with tandem catalysis. Tafel plot analysis revealed effective mass transport for C2+ product generation on the optimized wrinkled gold-copper tandem electrode, attributed to the local *CO production by the tandem catalyst, facilitating enhanced C-C coupling on the copper catalyst compared to a purely copper based electrode. Experimental results show that the design and manipulation of the morphology of the tandem catalyst electrode achieved via step-by-step optimization can significantly enhance the selectivity and activity of the catalyst in converting CO2 to desired fuels and chemicals.

Direct reduction of CO2 to carbon material on liquid cathode in molten salts

This study presents a novel method for the direct reduction of CO2 to produce carbon materials on a liquid cathode in high-temperature molten salts. CO2 gases were introduced into a Sn-Li liquid alloy, and they were subsequently reduced to solid carbons by the Li in the alloy. Unreacted CO2 gases were absorbed as carbonate ions (CO32−) in molten salts containing oxide ions (O2−). Subsequently, these carbonate ions were electrochemically reduced to solid carbons on the liquid cathode surface. Consequently, the current density was five times higher than that achieved using the conventional method without bubbling CO2 into the liquid cathode. The enhanced current density can be attributed to the combined thermochemical reduction of CO2 by Li and the electrochemical reduction of CO32−. This combination was realized for the first time at a relatively positive potential range, where pure Li or Ca cannot be deposited, leading to the carbon yield of over 90 % relative to CO2 feed reached. The resulting carbons contained a trace amount of Sn, which could be removed by washing after milling. These results show the potential for efficient and sustainable carbon capture and conversion technologies using liquid cathodes in high-temperature molten salts for CO2 reduction.

Highly enhanced photocatalytic performance for CO2 reduction on NH2-MIL-125(Ti): The impact of (Cu, Mn) co-incorporation

Photocatalytic CO2 reduction has been considered as an efficient way for the carbon nuetrality. In this work, a series of (Cu, Mn) co-incorporated metal-orgnaic frameworks (MOFs) (NH2-MIL-125(Ti) (NML)) with different Cu2+/Ti4+ and Mn2+/Ti4+ molar ratios are systematically investigated to improve the efficiency for photocatalytic CO2 reduction. The optimized sample (1 M−5C−−NML) shows a highest yield of HCOOH (116.74 μmol.g−1.h−1) (3.71 times higher than that of NML), and a superior apparent quantum efficiency (AQE) (6.74 % at 405 nm). The improved performance is attributed to the formed oxygen vacancy and intermediate energy level as introduced by the co-incorporation, which facilitate the charge separation and enhance the visible-light-harvesting of NML. It shows that the density of oxygen vacancies increases with the increasing amount of Cu, resulting in enhanced charge separation. However, the increasing amount of Mn leads to the short-range Mn-Mn interaction, the concentration quenching effect as well as the inhibited photocatalytic performance. This work shows that the co-incorporated MOFs can be used as an advanced photocatalyst.

The effect of carbon supports on the electrocatalytic performance of Ni-N-C catalysts for CO2 reduction to CO

Carbon-supported nickel and nitrogen co-doped (Ni-N-C) catalysts have been extensively studied as selective and active catalysts for CO2 electroreduction to CO. Most studies have focused on adjusting the coordination structure of Ni-Nx active sites, while the impact of the carbon supports has often been overlooked. In this study, a series of Ni-N-C catalysts on different carbon supports, including carbon black (CB), multi-walled carbon nanotubes (CNT), and activated nitrogen-doped biochar (ANBC), were synthesized using a ligand-mediated method. The effect of the carbon support on the electrocatalytic performance for CO2 reduction was investigated at both low current densities, in a H-cell, and high current densities, in a MEA electrolyzer. All of the prepared Ni-N-C catalysts show good faradaic efficiencies (FE) toward CO production (up to ~90%), however, the onset potentials and partial current densities for CO production vary greatly. The textural properties of the carbon support and the distribution of Ni-Nx active sites on the carbon support are demonstrated as the main factors behind the performance differences. In particular, hierarchical porous structures with large specific surface area are helpful to facilitate mass transport and improve the dispersion of active sites, which allows for a better CO2 reduction performance of Ni-N-ANBC compared to Ni-N-CB and Ni-N-CNT. This study demonstrates the importance of the carbon support for Ni-N-C catalysts and provides new insights into the design of efficient Ni-N-C catalysts for the CO2RR.

Modulating the local electron density at built-in interface iron single sites in Fe-CN/MoO3 heterostructure for enhanced CO2 reduction to CH4 and Photo-Fenton reaction

The catalytic efficiency of heterogeneous photocatalytic CO2 reduction and photo-Fenton H2O2 activationisclosely related to the local electron density of reaction center atoms. However, electron-hole recombination from random charge transfer significantly restricts the targeted electron delivery to the active center. Herein, Fe-C3N4/MoO3 heterojunction with interfacial coordination of atomically dispersed Fe-N4 sites with the O interface of MoO3 was synthesized by simple hydrothermal method. Based on the experimental results and density functional theory calculation (DFT), the heterojunction structure fosters accelerated interfacial electron transfer due to directional interfacial electric field (IEF) between Fe-CN and MoO heterogeneous interfaces, and the interfacial bond between Fe-N4 sites and O at the built-in interface regulates the local electron density of Fe-N4 active center. DFT further reveals that the interfacial electron flow and concentrated electron density at Fe-N4 sites result from the coordination between Fe-N4 and MoO3 interfaces. This directs electron flow towards the Fe center, significantly enhancing CO2 adsorption and H2O2 conversion efficiency. PDOS analysis shows that the dyz and dz2 orbitals of the isolated Fe atom in Fe-CN overlap with the pz orbital of the O atom in MoO3, playing a pivotal role in CO2 adsorption. Consequently, the Fe-CN/MoO3 heterojunction demonstrated highly efficient photocatalytic CO2 reduction to CH4, coupled with benzyl alcohol oxidation and photo-Fenton tetracycline degradation. These findings offer a promising multifunctional catalyst strategy for the development of energy conversion and environmental remediation.

Slow-light-driven photocatalytic CO2 reduction to CH4 mediated by photonic crystal Graphdiyne-Cu/ZnO Z-scheme system

Developing photocatalysts with high activity and selectivity remains a significant challenge in the field of CO2 photoreduction for producing valuable chemical or fuel products under mild conditions. Herein, photonic crystal (PC) GDY-Cu/ZnO was constructed through the in-situ induced growth of graphdiyne (GDY) on PC Cu/ZnO surface via H2-reduction for efficient photoreduction of CO2 to CH4. With the aid of photonic crystal structure, PC GDY-Cu/ZnO exhibits a distinctive red-edge slow light region which can significantly improve the utilization efficiency of visible light and intensify photo-catalysis. Additionally, the formed all-solid-state Z-scheme system efficiently accelerates photoelectron migration, facilitating e-/h+ separation. Thirdly, the surface GDY, along with the enrich oxygen vacancies generated during H2 reduction, enhances the adsorption and activation toward CO2 and H2O on PC GDY-Cu/ZnO interface. In consequence, PC GDY-Cu/ZnO demonstrates highly photocatalytic conversion of CO2 to CH4, achieving a CH4 yield of 33.67 μmol·g−1·h−1 with 93.3 % selectivity via slow-light-driven photocatalysis CO2 reduction. This work provides an efficient strategy to modify ZnO for the efficient photoreduction of CO2 to CH4.

Altering preferential product selectivity in electrocatalytic CO2 reduction over fluorine-modified CuIn bimetallic materials

Integrating carbon dioxide (CO2)-derived renewable technologies into the petrochemical industry presents a promising avenue for carbon neutrality. The renewable-energy-powered electrochemical CO2 reduction (eCO2R) process, particularly over Cu-based electrocatalysts, is a valuable asset for our decarbonization efforts to avoid climate consequences. Intending to enhance process efficiency, this work is a distinctive case study emphasizing the need to develop electrocatalysts in conjunction with adjusting operating conditions. A representative case is presented using fluorine-modified CuIn bimetallic electrocatalysts with tunable In/Cu ratios, demonstrating how to alter selectivity preferences based on reactor configuration: Our optimized catalyst system led to the highest faradaic efficiency (FE) for C2+ products of 68 % and the highest C1 FE of 80 % using gas diffusion electrodes (GDE)- and H-cell-type based electrolyzer, respectively. Moreover, the controllable In/Cu ratio and the degree of fluoride doping played a pivotal role in governing the physicochemical properties of the bimetallic electrocatalysts and their eCO2R performance. Diverse characterization tools offered systematic insights into the relationships between catalyst structure and properties, reactor configuration, electrolyte, and performance, aiming to enhance the Technology Readiness Level of the eCO2R process.

Novel Two-dimensional Tellurophosphates: Visible Light Photocatalysts for Water Splitting and Carbon Dioxide Reduction

Exploring efficient two-dimensional (2D) photocatalysts for solar-driven water splitting into hydrogen and oxygen is crucial for sustainable hydrogen energy production. In this study, we investigated the suitability of novel 2D tellurophosphates M2P2Te6 (M=Mg, Ca, Sr, Ba, Ra) for photocatalytic overall water splitting using density functional theory (DFT) approach. The stability of tellurophosphates was assessed based on formation energies, phonon dispersions, ab initio molecular dynamics, and elastic modulus results. These monolayers have desirable direct bandgaps (∼1.6 – 2.2 eV) for efficient light absorption, and their valence and conduction bands ideally straddle both the oxidation and reduction potential of water along with the ability to reduce CO2 to hydrocarbons or carbonaceous products. Moreover, Gibbs free energies of Hydrogen Evolution Reaction (HER) and Oxygen Evolution Reaction (OER) of tellurophosphate monolayers are also computed and display that these monolayers are viable photocatalysts under the influence of applied external potential. The tellurophosphates monolayers show strong optical absorption, with an absorption coefficient reaching up to 105 cm-1, across both the visible and UV regions of the solar spectrum, accompanied by high carrier mobility (order of 103 cm2 V-1s-1). The predicted solar-to-hydrogen efficiency of all monolayers exceeds 12%, fulfilling the criteria for commercial and economic viability in solar hydrogen production. The theoretical findings of current study imply that novel 2D tellurophosphate monolayers are promising candidates for optoelectronics, especially as photocatalysts for overall water splitting and CO2 reduction.

TM@MoSSe (TM = Ni, Fe) as novel electrocatalysts for reduction of CO2 to CO: A DFT study

It is crucial to develop highly efficient, selective and low-overpotential electrocatalysts for CO2 reduction. This paper proposes an efficient iron and nickel single-atom catalyst using Janus MoSSe as the substrate to reduce CO2 to CO by using DFT calculations. The adsorption of a single TM atom like Fe, Co, Ni, Ru, Rh, Pd, Os, Ir and Pt on Janus MoSSe monolayer results in a decrease in band gap, which may accelerate the catalytic CO2 reduction. The excellent catalytic activity of Fe@MoSSe and Ni@MoSSe is owing to the high d-band center and hence the strong TM-CO2 bonding. The asymmetric structure of Janus MoSSe creates the local built-in electric field, which further increases by about 8% or 0.8% after the adsorption of single Ni or Fe atom so as to afford the better electrocatalytic performances for reduction of CO2 to CO in both TM modified systems. So, this work proposes the catalysts Fe@MoSSe and Ni@MoSSe with good selectivity and activity for CO2 reduction by revealing their underlying mechanisms, and Janus MoSSe may be used as a potential substrate material for CO2 reduction catalysts.

Ag Atom Induces Microstrain Environment around Cd Sites to Construct Diatomic Sites for Almost 100% CO2-to-CO Electroreduction.

Deeply understanding how local microstrain environment around diatomic sites influences their electronic state and adsorption is crucial for improving electrochemical CO2 reduction (eCO2R) reaction; however, precise engineering of the atomic microstrain environment is challenging. Herein, we fabricate Ag-CdTMT electrocatalysts with AgN2S2-CdN2S2 diatomic sites by anchoring Ag to the nodes of CdTMT (TMT = 2,4,6-trimercaptotriazine anion) coordination polymers. The Ag-CdTMT catalysts achieve approximately 100% Faradaic efficiency for CO reduction with an industrial level current density (∼200 mA cm-2 in H-cell). The embedded Ag atoms induce the formation of Ag-Cd diatomic sites with local microstrain, stretching Cd-N/S bonds, and reinforcing electron localization at Cd sites. The microstrain engineering and adjacent Ag atoms synergistically reduced Cd 4d-C 2p antibonding orbital occupancy for intensifying *COOH adsorption as the rate-determining step. This study provides novel insights into customizing the electronic structure of diatomic sites through strain engineering.

Conversion of C4F8 via plasma catalysis over Al2O3/Zr/SO4-2 catalyst: Effects of H2O(g)

Reducing the emission of octafluorocyclobutane (C4F8) which has a high global warming potential (GWP) of 10,300 is essential. This study investigated the effectiveness of C4F8 removal achieved with plasma catalysis system. Effects of Ar content in the gas stream and inlet C4F8 concentration on C4F8 conversion efficiency were evaluated with two types of catalysts including Al2O3 (A) and Al2O3 /ZrO2/SO42-(AZS). Results demonstrated a linear correlation between Ar content with C4F8 conversion, and energy efficiency (EE). Lissajous figure analysis coupled with BOLSIG + simulations revealed that the AZS catalyst applied increased the mean electron energy (MEE) to 2.68 eV and modified the electron energy distribution function (EEDF), likely contributing to its superior performance. At a C4F8 concentration of 400 ppm, the AZS catalyst coupled with plasma achieved 80 % conversion with an EE of 1.85 g/kWh. Interestingly, at an optimal inlet C4F8 concentration of 5,000 ppm, the highest EE (11 g/kWh) was obtained with a C4F8 conversion efficiency of 18 %. The addition of H2O(g) as a reactant resulted in complete C4F8 conversion when AZS catalyst was applied. The optimal plasma-catalytic conditions determined through C4F8 conversion, EE and CO2 equivalent (CO2e) assessments, yielded a CO2e emission (CO2e) to CO2 reduction (CO2r) ratio of 1:9.09. Product analysis revealed the formation of CO2, CO, and HF during C4F8 conversion with AZS catalyst in the presence of H2O(g). The system was operated at 12 kV for the gas stream containing 50 % Ar and N2 as carrier gas at a flow rate of 100 mL/min. These findings highlight the potential of plasma catalysis for the effective abatement of C4F8, offering a promising strategy for mitigating its environmental impact.

Computational screening of 2D ternary penta-materials with auxetic properties and efficient photocatalytic CO2 reduction

Due to unique structural and electronic properties, pentagon-based two-dimensional (2D) materials have captured significant interest in recent years. However, previous studies on these materials have primarily focused on unary and binary systems, with less exploration of ternary pentagonal structures. Herein, we conducted first-principles calculations to evaluate the stability of 122 ternary pentagonal monolayers composed of metals, nitrogen, and chalcogen. We identify six highly stable candidates, including AuNS, CuNTe, GaNS, InNS, SbNS, and SbNSe that meet the criteria for thermodynamic, mechanical, and dynamic stability. Mechanical property analysis reveals that five of these monolayers demonstrate auxetic behavior. Electronic structure calculations show that all candidates are semiconductors with band gaps ranging from 0.12 to 3.42 eV. Specifically, the SbNS and SbNSe monolayers are indirect semiconductors with band gaps of 2.25 and 2.27 eV, respectively. These materials exhibit strong visible light absorption, and potentially serve as exceptional photocatalysts for the reduction of CO2 to CH4 due to the optimal band alignment. The free energy change in the rate-limiting step is even lower than those found in g-C3N4 and MoS2-based systems. Our findings highlight new pentagon-based 2D materials with remarkable electronic, mechanical, and optical properties, making them promising candidates for applications in mechanics and energy conversion.

Incorporating perovskites in photovoltaic-powered electrochemical cells for a sustainable future: An inclusive review

Due to the escalating demand for energy across all sectors, traditional energy sources are proving insufficient to meet our requirements. Moreover, their extensive use is exacerbating environmental issues. Consequently, solar energy has garnered significant attention due to its affordability, cleanliness, and abundance. This review presents an analysis of various solar cell systems, comparing their efficiency, cost, and stability based on literature spanning the past decade. While perovskite-based solar cells have demonstrated promising performance in laboratory settings, challenges with stability hinder their industrial-scale implementation. On the other hand, perovskites exhibit favorable catalytic properties, making them suitable for the electrochemical reduction of CO2. To address stability concerns, this review proposes structural engineering approaches aimed at maximizing electricity generation from solar energy to power electrochemical cells for CO2 reduction in the environment.

Fluorine-regulated Cu catalyst boosts electrochemical reduction of CO2 towards ethylene production

Electrochemical reduction of carbon dioxide (CO2RR) into value-added multi-carbon (C2) products utilizing renewable energy is a promising way to reduce carbon emission and achieve carbon neutrality. However, rational design of catalysts towards high C2 products selectivity remains a formidable task. Herein, fluorine modified copper catalyst was synthesised by thermal anneal in the presence of ammonium fluoride and sequential annealing in argon atmosphere. The charge distribution and coordination environment on copper surface were adjusted by doped fluorine atoms, which enables the formation of key intermediates and their sequential evolution into ethylene. The catalyst achieves a remarkable Faradaic efficiency (FE) of 40.6 % for eCO2RR to ethylene and remains stable over 13 hours. Density functional theory calculations indicates that the excellent CO2RR performance can be attributed to the suppressed hydrogen evolution on fluorine-doped copper catalyst. Our work brings a potential modification strategy of Cu-based catalyst for electrolytic CO2-to-C2 pathway.

Enhancing CO2 electroreduction to formate on bismuth catalyst via sulfur doping

The electrochemical reduction of CO2 to formate is an effective approach to achieving carbon neutrality. However, the instability of catalyst remains a significant limitation. Doping heteroatoms is a recognized method for tuning the coordination environment to enhance both electrochemical performance and stability. Herein, we report a facile and mild hydrothermal method employing sulfur doping to tune the coordination environment of bismuth active sites. Sulfur doping modifies the coordination environment of active sites by partially substituting O atoms bonded with bismuth active sites and simultaneously creating an abundance of oxygen vacancies, which effectively stabilize the active sites. This results in notably improved stability, reaching 110 h with a significant FEHCOOH (around 100 %). The bismuth-based catalyst modified with sulfur exhibits an impressive FEHCOOH over 95 % across a wide applied potential range of −0.7 to −1.4 VRHE. The flower-like structure increases the electrochemical surface area, promoting greater exposure of bismuth active sites. This leads to a high formate production rate of 1248 mmol∙h-1∙cm-2 for the Cu-BiS catalyst, which is 1.7 times that of the Cu-Bi catalyst. This strategy provides an effective way to tune the coordination environment of active sites and stabilize them.