Electrocatalytic Reduction Of Carbon Dioxide Research Articles

Atomic Design of Copper Active Sites in Pristine Metal-Organic Coordination Compounds for Electrocatalytic Carbon Dioxide Reduction.

Electrocatalytic carbon dioxide reduction reaction (CO2RR) has emerged as a promising and sustainable approach to cut carbon emissions by converting greenhouse gas CO2 to value-added chemicals and fuels. Metal-organic coordination compounds, especially the copper (Cu)-based coordination compounds, which feature well-defined crystalline structures and designable metal active sites, have attracted much research attention in electrocatalytic CO2RR. Herein, the recent advances of electrochemical CO2RR on pristine Cu-based coordination compounds with different types of Cu active sites are reviewed. First, the general reaction pathways of electrocatalytic CO2RR on Cu-based coordination compounds are briefly introduced. Then the highly efficient conversion of CO2 on various kinds of Cu active sites (e.g., single-Cu site, dimeric-Cu site, multi-Cu site, and heterometallic site) is systematically discussed, along with the corresponding catalytic reaction mechanisms. Finally, some existing challenges and potential opportunities for this research direction are provided to guide the rational design of metal-organic coordination compounds for their practical application in electrochemical CO2RR.

Surface Facets Reconstruction in Copper-Based Materials for Enhanced Electrochemical CO2 Reduction.

The unavoidable and unpredictable surface reconstruction of metallic copper (Cu) during the electrocatalytic carbon dioxide (CO2) reduction process is a double-edged sword affecting the production of high-value-added hydrocarbon products. It is crucial to control the surface facet reconstruction and regulate the targeted facets/facet interfaces, and further understand the mechanism between activity/selectivity and the reconstructed structure of Cu for CO2 reduction. Based on the current catalyst design methods, a facile strategy combining chemical reduction and electro-reduction is proposed to achieve specified Cu(111) facets and the Cu(110)/(111) interfaces in reconstructed Cu derived from cuprous oxide (Cu2O). The surface facet reconstruction significantly boosted the electrocatalytic conversion of CO2 into multi-carbon (C2+) products comparing to the unmodified catalyst. Theoretical and experimental analyses show that the Cu(110)/(111)s interface between Cu(110) and a small amount of Cu(111) can tailor the reaction routes and lower the reaction energy barrier of C-C coupling to ethylene (C2H4). The work will guide the surface facets reconstruction strategy for Cu-based CO2 electrocatalysts, providing a promising paradigm to understand the structural variation in catalysts.

Investigating the influence of oxygen doping in modulating product distribution for electrocatalytic CO2 reduction reaction

Efficient carbon recycling hinges on a comprehensive understanding of the mechanics behind electrocatalytic carbon dioxide reduction reactions (ECO2RR). Here, we have engineered, in-situ growth of CuO featured on O-doped gCN (COG) and ex-situ growth of CuO on bare gCN (CG) respectively, functioned as platforms fordisengaging the fundamental of ECO2RR. The COG holds substantial capacity compared to CG for efficient conversion of CO2 into hydrocarbons and initiated the C2 product pathway with enlarged faradaic efficiency (FE). The experimental results indicate that the COG enhanced the product conversion of CH3OH (FE = 61.5% ± 0.5), C2H5OH (FE = 24.7% ± 0.5), and HCOO– (FE = 6.1% ± 0.5) at −1.1 V Vs RHE. Meanwhile, the CG exhibited the maximum conversion of CO2 into CH3OH (FE = 56.4% ± 0.5) at the same potential range. For the CG, the partial current density of CH3OH (JCH3OH) is −1.8 mA cm−2, whereas COG exhibited −4.9 mA cm−2. Interestingly, in this ECO2RR, the study of oxygen doping demonstrated that feasible CO2 conversion, due to its affinity towards CO2 and high donor density.

Linkage Engineering in Covalent Organic Frameworks for Metal-Free Electrocatalytic C2H4 Production from CO2.

Electrocatalytic carbon dioxide reduction reaction (CO2RR) to produce ethylene (C2H4) is conducive to sustainable development of energy and environment. At present, most electrocatalysts for C2H4 production are limited to the heavy metal copper, meanwhile, achieving metal-free catalysis remains a challenge. Noted piperazine with sp3 N hybridization is beneficial to CO2 capture, but CO2RR performance and mechanism have been lacking. Herein, based on linkage engineering, we construct a novel high-density sp3 N catalytic array via introducing piperazine into the crystalline and microporous aminal-linked covalent organic frameworks (COFs). Thanks to its high sp3 N density, strong CO2 capture capacity and great hydrophilicity, aminal-linked COF successfully achieves the conversion of CO2 to C2H4 with a Faraday efficiency up to 19.1%, which is stand out in all reported metal-free COF electrocatalysts. In addition, a series of imine-linked COFs are synthesized and combined with DFT calculations to demonstrate the critical role of sp3 N in enhancing the kinetics of CO2RR. Therefore, this work reveals the extraordinary potential of linkage engineering in COFs to break through some catalytic bottlenecks.

CuO (111) Microcrystalline Evoked Indium-Organic Framework for Efficient Electroreduction of CO2 to Formate.

Electrochemical reduction of carbon dioxide (CO2RR) to formate is economically beneficial but suffers from poor selectivity and high overpotential. Herein, enriched microcrystalline copper oxide is introduced on the surface of indium-based metal-organic frameworks. Benefiting from the CuO (111) microcrystalline shell and formed catalytic active In-Cu interfaces, the obtained MIL-68(In)/CuO heterostructure display excellent CO2RR to formate with a Faradaic efficiency (FE) as high as 89.7% at low potential of only -0.7 V vs. RHE in a flow cell. Significantly, the membrane electrode assembly (MEA) cell based on MIL-68(In)/CuO exhibit a remarkable current density of 640.3mAcm-2 at 3.1V and can be stably operated for 180h at 2.7 V with a current density of 200mAcm-2. The ex/in situ electrochemical investigations reveal that the introduction of CuO increases the formation rate of the carbon dioxide reduction intermediate *HCOO- and inhibits the competitive hydrogen evolution reaction. This work not only provides an in-depth study of the mechanism of the CO2RR pathways on In/Cu composite catalyst but also offers an effective strategy for the interface design of electrocatalytic carbon dioxide reduction reaction.

2D zirconium-based metal-organic framework/bismuth(III) oxide nanorods composite for electrocatalytic CO2-to-formate reduction

Electrocatalytic carbon dioxide reduction reaction (eCO2RR) represents one of the most promising technologies for sustainable conversion of CO2 to value-added products. Although metal-organic frameworks (MOFs) can be vastly functionalized to create active sites for CO2RR, low intrinsic electrical conductivity always makes MOFs unfavorable candidates for eCO2RR. Besides, studies on how to regulate eCO2RR activity of MOFs from linkers' functionalities viewpoint lag far behind when compared with the assembly of multinuclear metal-centered clusters. In this work, non-toxic bismuth(III) oxide (Bi2O3) was incorporated into a series of two-dimensional (2D) MOFs (ZrLX) established from Zr-oxo clusters and triazine-centered 3-c linkers with different functionalities (LX = 1–5) to give composites ZrLX/Bi2O3. To investigate how functionalities on linkers distantly tune the eCO2RR performance of MOFs, electron-donating/withdrawing groups were installed at triazine core or benzoate terminals. It is found that ZrL2/Bi2O3 (‒F functionalized on triazine core) exhibits the best eCO2RR performance with the highest Faradaic efficiency (FE) of 96.73% at −1.07 V vs. RHE, the largest electroactive surface (Cdl = 4.23 mF cm−2) and the highest electrical conductivity (5.54 × 10−7 S cm−1), highlighting tuning linker functionalities and hence electronic structure as an alternative way to regulate eCO2RR.

Single-atom anchored on curved boron nitride fullerene surface as efficient electrocatalyst for carbon dioxide reduction

Electrocatalytic carbon dioxide reduction reaction (CO2RR) is currently one of the most promising methods for conversion of excessive CO2 emission. In this study, the electrocatalytic performance of transitional-metal atoms anchored on defective boron nitride fullerene of different size were systematically investigated by density functional theory study (TM= Sc, Ti, V, Cr, Mn, Fe, Ni, Zn, and Mo). The results showed Mn-B23N24 and Fe-B23N24 exhibited high activity and selectivity for CO2RR to CH4. Analysis of the high catalytic performance origin indicates the binding energy of *CO and *OH intermediates (Eb(*CO) and Eb(*OH)) can server as descriptors for the catalytic performance. The curvature effect of the boron nitride fullerene surface on the catalytic performance was analyzed by the so-called pyramidalization angle which shows TM-N3 center with the pyramidalization angle of about 26° exhibits the highest activity. The analysis of the coordination environment also reveals B defects are more favorable for regulating catalytic activity compared with N defects. Especially, compare with the Mn doped BN nanosheet, the limiting potential is significantly decreased from −0.64 V on the flat nanosheet to −0.25 V on TM doped B defective B24N24, highlighting the importance of the curvature effect on the CO2RR performance. This study demonstrated that metal-doped boron nitride fullerene with appropriate curvature is high potential to be efficient CO2RR catalysts, providing valuable insights for the rational design of CO2RR electrocatalysts with high-efficiency.

Efficient electroreduction of carbon dioxide to formate enabled by bismuth nanosheets enriched dual [formula omitted] vacancy

The electrocatalytic reduction of carbon dioxide (CO2ER) into formate presents a compelling solution for mitigating dependence on fossil energy and green utilization of CO2. Bismuth (Bi) has been gaining recognition as a promising catalyst material for the CO2ER to formate. The performance of Bi catalysts (named as Bi-V) can be significantly improved when they possess single metal atom vacancy. However, creating larger-sized metal atom vacancies within Bi catalysts remains a significant challenge. In this work, Bi nanosheets with dual VBi0 vacancy (Bi-DV) were synthesized utilizing in situ electrochemical transformation, using BiOBr nanosheets with triple vacancy associates (VBi″′VO···VBi″′, VBi″′ and V•• O denote the Bi3+ and O2− vacancy, respectively) as a template. The obtained Bi-DV achieved higher CO2ER activity than Bi-V, showing Faradaic efficiency for formate production of >92% from -0.9 to -1.2 VRHE in an H-type cell, and the partial current density of formate reached up to 755 mA/cm2 in a flow cell. The comprehensive characterizations coupled with density functional theory calculations demonstrate that the dual VBi0 vacancy on the surface of Bi-DV expedite the reaction kinetics toward CO2ER, by reducing the thermodynamic barrier of *OCHO intermediate formation. This research provides critical insights into the potential of large atom vacancies to enhance electrocatalysis performance.

Study on the Inhibition of Hydrogen Evolution Reaction by Electrocatalytic Reduction of Carbon Dioxide Using Elsholtzia Harchowensis Biochar

With the widespread application of plant remediation technology in the field of soil remediation, there was an increasing stock of hyperaccumulating plant tissues containing heavy metals, but there was currently a lack of effective disposal methods. In the preliminary research process, researchers used the copper hyperaccumulating plant Elsholtzia Harchowensis to prepare biochar material electrodes and successfully used them in the electrocatalytic reduction of carbon dioxide (CO2) process. Due to the previous research being conducted in aqueous solutions, the hydrogen evolution reaction (HER) on the working electrode surface has a certain impact on the Faraday efficiency (FE) of carbon-containing products. In order to further improve the electrocatalytic reduction performance of biochar materials, this study was based on B- and N-doped biochar prepared from Elsholtzia Harchowensis as raw material. The influence mechanisms of electrode surface hydrophobicity and electrolyte components (PC/water) on the CO2RR and HER were studied, respectively. After dropwise coating PTFE on the surface of Cu/C-BN material, the hydrophobicity of Cu/C-BN-PT material was improved, and the effect on the active sites of the catalyst was relatively small without changing the structure and elemental characteristics of the original electrode. In a 1.0 M KHCO3 solution, the Faraday efficiency of H2 in Cu/C-BN-PT material decreased by 20.1% compared to Cu/C-BN at −0.32 V (vs. RHE), indicating that changing the hydrophilicity of the material can significantly inhibit the HER. In a solution of PC/water at a ratio of 9:1 (V:V), the FE of converting CO2 to methane (CH4) at −0.32 V (vs. RHE) reached 12.0%, and the FE of carbon monoxide (CO) reached 64.7%. The HER was significantly inhibited, significantly improving the selectivity of electrocatalytic CO2.

Efficient Electrocatalytic Reduction of CO2 to CO by Cu‐doped Carbon Materials Derived from ZIF‐8

AbstractElectrochemical reduction of carbon dioxide presents a promising pathway to tackle global energy and environmental challenges. Porous carbon materials from metal‐organic frameworks exhibit high specific surface area, abundant active sites, and adjustable pore structure, demonstrating excellent electrocatalytic performance. With their abundant resources and tunability, copper‐based catalysts are well‐suited for efficient carbon dioxide conversion. However, the selectivity and stability of copper‐based catalysts is poor. This study presents the preparation of the first Cu‐doped ZIF‐8‐derived carbon materials and investigates their effect on electrocatalytic carbon dioxide reduction. At the optimal potential of −0.7 V vs. RHE, the CO Faradaic Efficiency (FE) of the Cu0.5‐N−C catalyst reaches 89 %. Furthermore, the electrochemical current density and CO FE of Cu0.5‐N−C catalyst remain nearly unchanged within 13 hours in 0.1 mol L−1 KHCO3 electrolyte. Compared to most of the reported copper‐based catalysts, Cu0.5‐N−C exhibits better stability. Characterization results show that Cu0.5‐N−C has a larger Cu‐N4, higher pyridinic N content, larger specific surface area, and average pore size, which help promote CO2 adsorption and enhance catalyst stability. This work provides new insights and pathways for electrocatalytic carbon dioxide reduction, with enormous potential to contribute to the global energy transition and environmental protection.

Coordination Environment Engineering of Metal Centers in Coordination Polymers for Selective Carbon Dioxide Electroreduction toward Multicarbon Products.

Electrocatalytic carbon dioxide reduction reaction (CO2RR) toward value-added chemicals/fuels has offered a sustainable strategy to achieve a carbon-neutral energy cycle. However, it remains a great challenge to controllably and precisely regulate the coordination environment of active sites in catalysts for efficient generation of targeted products, especially the multicarbon (C2+) products. Herein we report the coordination environment engineering of metal centers in coordination polymers for efficient electroreduction of CO2 to C2+ products under neutral conditions. Significantly, the Cu coordination polymer with Cu-N2S2 coordination configuration (Cu-N-S) demonstrates superior Faradaic efficiencies of 61.2% and 82.2% for ethylene and C2+ products, respectively, compared to the selective formic acid generation on an analogous polymer with the Cu-I2S2 coordination mode (Cu-I-S). In situ studies reveal the balanced formation of atop and bridge *CO intermediates on Cu-N-S, promoting C-C coupling for C2+ production. Theoretical calculations suggest that coordination environment engineering can induce electronic modulations in Cu active sites, where the d-band center of Cu is upshifted in Cu-N-S with stronger selectivity to the C2+ products. Consequently, Cu-N-S displays a stronger reaction trend toward the generation of C2+ products, while Cu-I-S favors the formation of formic acid due to the suppression of C-C couplings for C2+ pathways with large energy barriers.

Comparative life cycle analysis on ethylene production from electrocatalytic reduction of carbon dioxide

Ethylene is one of the largest greenhouse gas emitters and the most diversly used commodity chemicals globally. Electrocatalytic reduction of CO2 to ethylene received great attention from the research society to decarbonize the ethylene production. In this study, a life-cycle analysis is conducted using the Greenhouse Gases, Regulated Emissions, and Energy use in Technologies (GREET) model on the three electrocatalytic CO2-reduction pathways (or “e-ethylene” pathways): i) cascade conversion via carbon monoxide intermediate; ii) single-step conversion in membrane electrode assembly (MEA); and iii) single-step conversion in alkaline flow cell. The results showed that the electricity consumption is the lowest for the cascade pathway (164 MJ/kg), thus resulting in the lowest cradle-to-gate carbon intensity [18 kgCO2e/kg with United States (US) average grid)] among the three pathways followed by the single-step MEA (32 kgCO2e/kg) and then by the single-step alkaline (56 kgCO2e/kg). However, all three e-ethylene pathways were significantly more carbon-intensive than their fossil-based counterpart (1.1 kgCO2e/kg) due to their excessive energy consumption with the current state of technology. With renewable electricity, all three pathways yielded negative carbon intensity: from −3.1 kgCO2e/kg to −1.6 kgCO2e/kg depending on the source of CO2. The threshold carbon intensity of electricity (TCIE), defined as the upper bound of the carbon intensity of electricity to achieve lower carbon intensity for e-ethylene compared to fossil-based ethylene, is calculated for both current and future state of e-ethylene technologies. The cascade pathway had the highest TCIE out of the three e-ethylene pathways for both current (92 gCO2e/kWh) and future (124 gCO2e/kWh) state of technologies. However, the carbon intensity of average US grid (i.e., 467 and 303 gCO2e/kWh for current and future projections) were higher than the TCIEs of the corresponding timeline. Thus, reducing electricity requirement for e-ethylene pathways and bringing low-carbon generation mix in the United States (US) grid faster than the current projection are both essential to decarbonize ethylene and its downstream chemicals/polymers.

Benzyl alcohol promoted electrocatalytic reduction of carbon dioxide and C2 production by Cu2O/Cu

Oxide-derived copper (OD-Cu)-based materials containing Cuδ+ (0 < δ ≤ 1) have been considered as promising electrocatalysts for electrochemical CO2 reduction reaction (ECO2RR) to produce valuable C2 products, which, however, suffer from poor stability, mainly due to the inevitable reduction of Cuδ+. We report here that the benzyl alcohol (BA) introduced in catholyte presents a markedly positive effect on the durability and C2 selectivity enhancement of ECO2RR when OD-Cu-based material is adopted as cathode electrocatalyst. The critical evidence of ECO2RR intermediates has been provided by in situ Raman and FTIR spectroscopy, which reveals the surface mechanisms of BA-assisted ECO2RR over OD-Cu catalysts. On the one hand, the introduction of BA increases the CO2 supply for ECO2RR by slowing down its neutralizing reaction, which results in the increased intermediate species coverage on the catalytic surface therefore the delayed self-reduction of Cuδ+; On the other hand, the interaction between BA and the intermediate species *CO during ECO2RR brings an enhanced selectivity of C2 products (FE C2 = 85.5 % at −1.38 V vs RHE). Besides, an energy-savings and economic electrolyzer can be achieved by coupling anodic BA oxidation reaction to benzoic acid and ECO2RR to C2 products with much lowered cell voltages.

Pulse Electrolysis Turns on CO2 Methanation through N‐Confused Cupric Porphyrin

AbstractBreaking the D4h symmetry in the square‐planar M−N4 configuration of macrocycle molecular catalysts has witnessed enhanced electrocatalytic activity, but at the expense of electrochemical stability. Herein, we hypothesize that the lability of the active Cu−N3 motifs in the N‐confused copper (II) tetraphenylporphyrin (CuNCP) could be overcome by applying pulsed potential electrolysis (PPE) during electrocatalytic carbon dioxide reduction. We find that applying PPE can indeed enhance the CH4 selectivity on CuNCP by 3 folds to reach the partial current density of 170 mA cm−2 at &gt;60 % Faradaic efficiency (FE) in flow cell. However, combined ex situ X‐ray diffraction (XRD), transmission electron microscope (TEM), and in situ X‐ray absorption spectroscopy (XAS), infrared (IR), Raman, scanning electrochemical microscopy (SECM) characterizations reveal that, in a prolonged time scale, the decomplexation of CuNCP is unavoidable, and the promoted water dissociation under high anodic bias with lowered pH and enriched protons facilitates successive hydrogenation of *CO on the irreversibly reduced Cu nanoparticles, leading to the improved CH4 selectivity. As a key note, this study signifies the adaption of electrolytic protocol to the catalyst structure for tailoring local chemical environment towards efficient CO2 reduction.

Pulse Electrolysis Turns on CO2 Methanation through N-Confused Cupric Porphyrin.

Breaking the D4h symmetry in the square-planar M-N4 configuration of macrocycle molecular catalysts has witnessed enhanced electrocatalytic activity, but at the expense of electrochemical stability. Herein, we hypothesize that the lability of the active Cu-N3 motifs in the N-confused copper (II) tetraphenylporphyrin (CuNCP) could be overcome by applying pulsed potential electrolysis (PPE) during electrocatalytic carbon dioxide reduction. We find that applying PPE can indeed enhance the CH4 selectivity on CuNCP by 3 folds to reach the partial current density of 170 mA cm-2 at >60 % Faradaic efficiency (FE) in flow cell. However, combined ex situ X-ray diffraction (XRD), transmission electron microscope (TEM), and in situ X-ray absorption spectroscopy (XAS), infrared (IR), Raman, scanning electrochemical microscopy (SECM) characterizations reveal that, in a prolonged time scale, the decomplexation of CuNCP is unavoidable, and the promoted water dissociation under high anodic bias with lowered pH and enriched protons facilitates successive hydrogenation of *CO on the irreversibly reduced Cu nanoparticles, leading to the improved CH4 selectivity. As a key note, this study signifies the adaption of electrolytic protocol to the catalyst structure for tailoring local chemical environment towards efficient CO2 reduction.

Constructing efficient bacterial cell factories to enable one‐carbon utilization based on quantitative biology: A review

AbstractDeveloping methylotrophic cell factories that can efficiently catalyze organic one‐carbon (C1) feedstocks derived from electrocatalytic reduction of carbon dioxide into bio‐based chemicals and biofuels is of strategic significance for building a carbon‐neutral, sustainable economic and industrial system. With the rapid advancement of RNA sequencing technology and mass spectrometer analysis, researchers have used these quantitative microbiology methods extensively, especially isotope‐based metabolic flux analysis, to study the metabolic processes initiating from C1 feedstocks in natural C1‐utilizing bacteria and synthetic C1 bacteria. This paper reviews the use of advanced quantitative analysis in recent years to understand the metabolic network and basic principles in the metabolism of natural C1‐utilizing bacteria grown on methane, methanol, or formate. The acquired knowledge serves as a guide to rewire the central methylotrophic metabolism of natural C1‐utilizing bacteria to improve the carbon conversion efficiency, and to engineer non‐C1‐utilizing bacteria into synthetic strains that can use C1 feedstocks as the sole carbon and energy source. These progresses ultimately enhance the design and construction of highly efficient C1‐based cell factories to synthesize diverse high value‐added products. The integration of quantitative biology and synthetic biology will advance the iterative cycle of understand–design–build–testing–learning to enhance C1‐based biomanufacturing in the future.

Porous structure based on Fenton reaction-assisted chemical etching of commercial silicon powder and its application for electrocatalytic reduction of carbon dioxide

Silicon-based porous nanocomposites are considered promising as electrode materials for the photoelectrochemical reduction of carbon dioxide. However, the high cost of raw materials and tedious processing for building nanostructures may not be conducive to large-scale industrial applications in terms of cost. Herein, we would like to introduce a porous structure prepared by Fenton reaction-assisted chemical etching of low-cost commercial silicon powder in the mixed solution of hydrogen fluoride and hydrogen peroxide. These porous particles are further decorated with silver nanoparticles to explore their feasibility for photoelectrochemical reduction of carbon dioxide. As shown by experimental results, this silicon-based nanocomposite is capable of catalyzing the conversion of carbon dioxide into carbon monoxide. The low cost of commercial silicon powder (~$3000/ton) compared with that of silicon wafers also renders this method potential and feasible for large-scale production of silicon-based porous materials.

Defect engineering of carbon-based electrocatalysts for the CO2 reduction reaction: A review

Electrocatalytic carbon dioxide (CO2) reduction is an important way to achieve carbon neutrality by converting CO2 into high-value-added chemicals using electric energy. Carbon-based materials are widely used in various electrochemical reactions, including electrocatalytic CO2 reduction, due to their low cost and high activity. In recent years, defect engineering has attracted wide attention by constructing asymmetric defect centers in the materials, which can optimize the physicochemical properties of the material and improve its electrocatalytic activity. This review summarizes the types, methods of formation and defect characterization techniques of defective carbon-based materials. The advantages of defect engineering and the advantages and disadvantages of various defect formation methods and characterization techniques are also evaluated. Finally, the challenges of using defective carbon-based materials in electrocatalytic CO2 reduction are investigated and opportunities for their use are discussed. It is believed that this review will provide suggestions and guidance for developing defective carbon-based materials for CO2 reduction.

Free‐standing Stanene for High Selectivity of Formate in Electrocatalytic Carbon Dioxide Reduction Reaction

AbstractAs well‐known electrocatalysts with good catalytic efficiency for carbon dioxide reduction reaction (CO2RR) towards the production of formate, tin (Sn)‐based catalysts have aroused broad concern. Here, free‐standing porous stanene is synthesized for the first time by a facile wet chemical method, and its excellent electrocatalytic performance for formate (HCOO−) formation in CO2RR is demonstrated. High Faradaic efficiency (F.E., 93% at −930 mV versus reversible hydrogen electrode (RHE)) can be achieved in the CO2RR catalyzed by stanene in 0.5 m KHCO3 aqueous solution. The in situ Mössbauer spectra reveal that zero‐valent Sn aids in improving the selectivity of formate production. Furthermore, density functional theory calculations suggest that the high selectivity of HCOO− of CO2RR on stanene mainly originates from the edge sites on Sn (100). To further explore the practicability of the stanene‐based catalysts for CO2RR, stanene decorated by 3 wt% BP‐2000 is prepared, showing an excellent F.E. of 98% at −930 mV versus RHE due to the higher exposure of catalytic active sites. These new findings of the activity origination and reaction mechanism of stanene contribute to the deeper understanding of Sn‐based catalysts for CO2RR, which is beneficial for the future designation of highly efficient CO2RR catalysts.

Recent Developments in Copper‐Based Catalysts for Enhanced Electrochemical CO2 Reduction

AbstractThe drastic climate change imposing adverse environmental effects receives serious research attention for finding a suitable solution. The replacement of conventional fossil energy sources with renewable and sustainable energy sources is the potential route; and thus, manifests as a viable solution. Accordingly, the electrocatalytic carbon dioxide (CO2) reduction process coupled with the renewable energy source is an emerging strategy for adopting a sustainable approach. However, the existing challenges in designing suitable catalyst, support material, electrolyte, inadequate selectivity, and intermediate reactions of CO2 reduction demand substantial research advancement. Numerous studies reported for the CO2 reduction process highlight the importance of catalyst design and product selectivity. Importantly, the copper‐based catalysts, capable in the output of multi‐carbon products, are reported as a “star” material. This review; therefore, focuses on catalyst design strategies, unique structural/morphological features, and product selectivity of diverse copper‐based catalysts. The outstanding findings of copper‐based catalysts and the corresponding products are critically discussed with adequate figures of merits. The impact of structural/morphological features on product selectivity is discussed in detail. The future scope and author perspectives on copper‐based catalysts for the feasible electrocatalytic CO2 reduction application are summarized.