Electrocatalytic Conversion Of CO2 Research Articles

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.

Regulating Cu Oxidation State for Electrocatalytic CO2 Conversion into CO with Near-Unity Selectivity via Oxygen Spillover.

Cu-based catalysts are the most intensively studied in the field of electrocatalytic CO2 reduction reaction (CO2RR), demonstrating the capacity to yield diverse C1 and C2+ products albeit with unsatisfactory selectivity. Manipulation of the oxidation state of Cu sites during CO2RR process proves advantageous in modulating the selectivity of productions, but poses a formidable challenge. Here, an oxygen spillover strategy is proposed to enhance the oxidation state of Cu during CO2RR by incorporating the oxygen donor Sb2O4. The Cu-Sb bimetallic oxide catalyst attains a remarkable CO2-to-CO selectivity approaching unity, in stark contrast to the diverse product distribution observed with bare CuO. The exceptional Faradaic efficiency of CO can be maintained across a wide range of potential windows of ≈700mV in 1m KOH, and remains independent of the Cu/Sb ratio (ranging from 0.1:1 to 10:1). Correlative calculations and experimental results reveal that oxygen spillover from Sb2O4 to Cu sites maintains the relatively high valence state of Cu during CO2RR, which diminishes the binding strength of *CO, thereby achieving heightened selectivity in CO production. These findings propose the role of oxygen spillover in CO2RR over Cu-based catalysts, and shed light on the rational design of highly selective CO2 reduction catalysts.

Rational Design of Local Reaction Environment for Electrocatalytic Conversion of CO2 into Multicarbon Products

AbstractThe electrocatalytic conversion of CO2 into multi‐carbon (C2+) products provides an attractive route for storing intermittent renewable electricity as fuels and feedstocks with high energy densities. Although substantial progress has been made in selective electrosynthesis of C2+ products via engineering the catalyst, rational design of the local reaction environment in the vicinity of catalyst surface also acts as an effective approach for further enhancing the performance. Here, we discuss recent advances and pertinent challenges in the modulation of local reaction environment, encompassing local pH, the choice of the species and concentrations of cations and anions as well as local reactant/intermediate concentrations, for achieving high C2+ selectivity. In addition, mechanistic understanding in the effects of the local reaction environment is also discussed. Particularly, the important progress extracted from in situ and operando spectroscopy techniques provides insights into how local reaction environment affects C−C coupling and key intermediates formation that lead to reaction pathways toward a desired C2+ product. The possible future direction in understanding and engineering the local reaction environment is also provided.

Theoretical research on efficient electrocatalysis of CO2 reduction reaction by borophene loaded transition metals

Electrocatalytic conversion of CO2 into chemical or fuel is regarded as a viable approach to attain energy conversion, chemical energy storage and carbon neutrality. Borophene exhibits great potential as an electrocatalyst owing to its exceptional physical and chemical attributes. β12-borophene incorporated transition metal (TM) as single atom catalysts (SACs) have been devised for the electrocatalysis of the carbon dioxide reduction reaction (CO2RR). Through the exploration of the most favorable CO2RR pathway and the comparison of Gibbs free energy (ΔG) during the potential determination step (PDS), the catalyst exhibiting remarkable catalytic activity for CO2RR are chosen. Wherein, the overpotential of Nb-β12 and Ru-β12 produce CO is only 0.02 and 0.03 V. The overpotential of Ru-β12 and Rh-β12 in generation of HCOOH product is only 0.03 and 0.06 V. Additionally, the catalytic performance of Rh-β12 in CO2 reduction to CH3OH and CH4 showcases exceptional performance, with overpotential of 0.65 and 0.79 V. Unexpectedly, the overpotential of Cd-β12 and Mo-β12 are 0.01 and 0.09 V for hydrogen evolution reaction (HER). The research offers invaluable insight for systematic designs and screening of catalysts for the electrochemical CO2RR.

Regulating the Cu2Se-SnO nanosheet heterostructure interface for efficient CO2 conversion to tunable syngas ratios

Electrocatalytic conversion of CO2 to syngas is an attractive pathway for transforming CO2 into high-value chemicals, but the process still suffers from low selectivity. In our work, we construct a two-dimensional (2D) structure of Cu2Se-SnO heterojunction catalyst through a high-temperature thermal reduction method. The catalyst with two phases located in the same plane exhibits efficient charge transfer, and the tunable heterojunction interface acts as active sites for CO2 adsorption and activation. Additionally, its suitable *CO adsorption energy facilitates the desorption of intermediates, leading to the formation of CO. Finally, this catalyst demonstrates excellent selectivity for syngas, maintaining a Faradaic efficiency (FE) of over 60% across a wide range of potentials (-0.67 ∼ −1.07 V vs. RHE) with adjustable syngas ratios and up to 92% FE at −0.97 V vs. RHE. This research provides a new approach for balancing reduction CO2 and competing hydrogen evolution reaction.

Atomic level dispersed nickel coupled with silver nanoparticle to boost the efficiency of CO2 conversion to CO via spin electrons regulation

Modulating the electronic configuration by coupling multi-scale active sites for electrocatalytic conversion of CO2 to CO is extremely challenging in terms of structural analysis and mechanism elucidation. Herein, a catalyst NiAD/AgNPs@CN with both atomic-level dispersed Ni and Ag nanoparticles on N-doped carbon substrate has been designed to reveal the true active sites and catalytic mechanism in complex materials. NiAD/AgNPs@CN exhibits CO Faraday efficiency (FECO) of 99.97% at −0.88 V (vs. RHE) in H-type cell and 91.77% FECO with a high current density of 79.70 mA/cm2 in flow cell. DFT calculations show that the tiny change in the energy level of spin electrons at atomic sites has a significant impact on the CO2 activation. The regulation of atomic Ni on Ag sites is the main reason for improving CO2RR performance. This work gives a new understanding on the catalytic mechanism of composite materials structured by atomic-level dispersed metal and nanoparticles.

Rapid screening of copper-based bimetallic catalysts via automatic electrocatalysis platform: Electrocatalytic reduction of CO2 to C2+ products on europium-modified copper

The electrocatalytic conversion of CO2 (CO2RR) to multi-carbon products has been an appealing strategy to reduce carbon emissions. However, rapid experimental discovery of efficient CO2RR electrocatalysts and fast recording of full product distribution information is non-trivial. Herein, we used an electrocatalyst testing platform featuring a home-built automatic flow cell to accelerate catalysts screening. Based on 364 effective data points from 42 Cu-lanthanide bimetallic catalysts obtained within 21 working hours, we found that Eu modification over Cu can promote C2+ faradaic efficiency (FE). We have previously reported part of the screening data and the optimization of the Mg-Cu catalyst（Angew. Chem.2022, 134, e202213423）. Here we augmented the dataset by adding the lanthanide modifiers and reported the Eu-Cu catalyst resulted from the high-throughput investigation. Our characterizations revealed that the Eu2+ reduced from Eu3+ during the catalyst synthesis prevented the agglomeration of nanoparticles, thus making europium modifications stand out from other lanthanide metal modifiers on FE C2+ enhancement. We then optimized the Eu-CuOx catalyst based on the above understanding to achieve ∼80% C2+ FE at a high current density of 1.25 A cm−2.

Role of Ionic Solvents in the Electrocatalytic CO2 Conversion and H2 Evolution Suppression: From Ionic Liquids to Deep Eutectic Solvents

AbstractThe ionic solvents, including both ionic liquids (ILs) and deep eutectic solvents (DES), are deeply studied for their potential in the carbon dioxide (CO2) capture and its further electrochemical conversion using different electrocatalysts. The aim of this review is to present and critically compare the role of ILs and DES in the activation of the electrochemical CO2 reduction reaction (CO2RR) and suppression of the hydrogen evolution reaction (HER). Therefore, the most relevant advances in the use of these ionic solvents in CO2RR, either as neat reaction medium or as electrolyte in molecular solvents, have been summarized and discussed. A special focus has been made on comparing the current density, overpotential, faradaic efficiency and products selectivity of the CO2RR in the presence of the ionic solvents and relaying those results with their chemical composition. Herein, the most recent strategies reported in the literature based on the use of either DES or ILs for enhancing the electrocatalytic CO2 conversion are reviewed, and some new perspectives based on immobilized ILs at the electrode surface are discussed.

Smart Electrode Surfaces by Electrolyte Immobilization for Electrocatalytic CO2 Conversion.

The activity and selectivity of molecular catalysts for the electrochemical CO2 reduction reaction (CO2RR) are influenced by the induced electric field at the electrode/electrolyte interface. We present here a novel electrolyte immobilization method to control the electric field at this interface by positively charging the electrode surface with an imidazolium cation organic layer, which significantly favors CO2 conversion to formate, suppresses hydrogen evolution reaction, and diminishes the operating cell voltage. Those results are well supported by our previous DFT calculations studying the mechanistic role of imidazolium cations in solution for CO2 reduction to formate catalyzed by a model molecular catalyst. This smart electrode surface concept based on covalent grafting of imidazolium on a carbon electrode is successfully scaled up for operating at industrially relevant conditions (100 mA cm-2) on an imidazolium-modified carbon-based gas diffusion electrode using a flow cell configuration, where the CO2 conversion to formate process takes place in acidic aqueous solution to avoid carbonate formation and is catalyzed by a model molecular Rh complex in solution. The formate production rate reaches a maximum of 4.6 gHCOO- m-2 min-1 after accumulating a total of 9000 C of charge circulated on the same electrode. Constant formate production and no significant microscopic changes on the imidazolium-modified cathode in consecutive long-term CO2 electrolysis confirmed the high stability of the imidazolium organic layer under operating conditions for CO2RR.

The Effect of Bismuth and Tin on Methane and Acetate Production in a Microbial Electrosynthesis Cell Fed with Carbon Dioxide.

This study investigates the impacts of bismuth and tin on the production of CH4 and volatile fatty acids in a microbial electrosynthesis cell with a continuous CO2 supply. First, the impact of several transition metal ions (Ni2+, Fe2+, Cu2+, Sn2+, Mn2+, MoO42-, and Bi3+) on hydrogenotrophic and acetoclastic methanogenic microbial activity was evaluated in a series of batch bottle tests incubated with anaerobic sludge and a pre-defined concentration of dissolved transition metals. While Cu is considered a promising catalyst for the electrocatalytic conversion of CO2 to short chain fatty acids such as acetate, its presence as a Cu2+ ion was demonstrated to significantly inhibit the microbial production of CH4 and acetate. At the same time, CH4 production increased in the presence of Bi3+ (0.1 g L-1) and remained unchanged at the same concentration of Sn2+. Since Sn is of interest due to its catalytic properties in the electrochemical CO2 conversion, Bi and Sn were added to the cathode compartment of a laboratory-scale microbial electrosynthesis cell (MESC) to achieve an initial concentration of 0.1 g L-1. While an initial increase in CH4 (and acetate for Sn2+) production was observed after the first injection of the metal ions, after the second injection, CH4 production declined. Acetate accumulation was indicative of the reduced activity of acetoclastic methanogens, likely due to the high partial pressure of H2. The modification of a carbon-felt electrode by the electrodeposition of Sn metal on its surface prior to cathode inoculation with anaerobic sludge showed a doubling of CH4 production in the MESC and a lower concentration of acetate, while the electrodeposition of Bi resulted in a decreased CH4 production.

Review of electrocatalytic reduction of CO2 on carbon supported films

Carbon capture and conversion are becoming increasingly important as atmospheric CO2 concentrations rise and their adverse effects become increasingly evident. CO2 conversion/utilization-related research has gained renewed interest on a variety of platforms, including thermal, solar, biological, photochemical, and electrochemical conversions. Electrochemical routes, using suitable catalysts, are potentially suitable for commercial purposes owing to ease of integration with solvent-based carbon capture processes. This paper summarizes and evaluates the studies conducted within the past decade regarding the feasibility of carbon-based supports utilized in electrocatalytic carbon dioxide reduction. CO2 conversion has been reviewed in a number of reports, focusing on specific sections, such as metallic/bimetallic catalysts, CO2 solubility, and the fabrication of electrodes and electrochemical cells. The number of publications addressing various carbon-based electrocatalysts is increasing, but these materials have not yet been reviewed. Herein, we are focused on three types of electrocatalyst materials: metals, metal-oxides, non-oxides, and combinations thereof with carbon. The scope of this study includes the following: i) carbon-based materials and how they are characterized by distinctive properties, ii) electrocatalytic CO2 conversion techniques, and iii) research cases for carbon allotrope-supported composites used in CO2 reduction. The advancement in analytical tools that provide insight into liquid-phase reactions will benefit the development of catalysts and electrodes that will be effective in converting CO2 into the desired products. Such developments will also be applicable to other systems involving liquid electrolytes or solvents for performing reactions on catalyst surfaces.

Ligand dominating the catalytic performance of cucurbit[6]uril modified gold nanoparticles for electrocatalytic CO2 reduction

Electrocatalytic conversion of CO2 into high-value products provides a promising means to solve the problem of the greenhouse effect and energy storage but is limited by its sluggish kinetics and poor selectivity. In this work, we report cucurbit[6]uril (CB[6]) modified gold nanoparticles (Au-CB[6] NPs) with different sizes (40 nm, 60 nm, and 80 nm) using a facile in situ method and investigate their electrocatalytic performance for CO2 reduction reaction (CO2RR). The 60 nm Au-CB[6] NPs exhibits exceptional selectivity for CO with the highest Faraday efficiency (FECO) reaching 97.6% at − 0.6 V vs. reversible hydrogen electrode (RHE) and excellent stability with FECO over 95% for 10 h. The partial current density of CO formed by 60 nm Au-CB[6] NPs is 8.1 mA/cm2, which is 18-fold that of 60 nm gold nanoparticles (Au NPs). Additionally, when the size increases from 40 nm to 80 nm, the CO selectivity of Au-CB[6] NPs remains around 97%, but that of Au NPs decreases from 81% to 61%. The ligand dominated catalytic performance of Au-CB[6] NPs can be attributed to the excess CB[6] coating on catalyst’s surface, which creates a CO2 enriched and hydrophobic environment. The CB[6] modification on Au NPs not only improves the catalytic activity, but it also suppresses the size effect for selectivity in electrocatalytic CO2RR, which proposes a universal strategy for other nanostructures to simplify preparation and separation process and still maintain decent catalytic performance.

Determination of local pH in CO2 electroreduction.

The electrocatalytic conversion of CO2 and H2O into fuels and valuable chemicals has gained significant interest as a prospective method for the storage of renewable energy and the utilization of captured CO2. In the process of electroreduction of CO2, pH near the surface of the electrocatalysts plays an important role in the catalytic selectivity and activity. However, to elucidate the local pH effect on the fundamental reaction mechanism and modify the catalytic CO2 reduction performance, the localized pH determination method is highly desirable. In this minireview, we present the recent advances in the strategies of the local pH probe for CO2 electrolysis in both H-type cell reactors and GDE-type flow electrolyzers, followed with a better understanding of the local reaction environment in CO2 reduction. Additionally, pertinent advantages and drawbacks of the different localized pH probe techniques are discussed, and perspectives on future research efforts are also provided in this minireview.

Review on strategies for improving the added value and expanding the scope of CO2 electroreduction products.

The electrochemical reduction of CO2 into value-added chemicals has been explored as a promising solution to realize carbon neutrality and inhibit global warming. This involves utilizing the electrochemical CO2 reduction reaction (CO2RR) to produce a variety of single-carbon (C1) and multi-carbon (C2+) products. Additionally, the electrolyte solution in the CO2RR system can be enriched with nitrogen sources (such as NO3-, NO2-, N2, or NO) to enable the synthesis of organonitrogen compounds via C-N coupling reactions. However, the electrochemical conversion of CO2 into valuable chemicals still faces challenges in terms of low product yield, poor faradaic efficiency (FE), and unclear understanding of the reaction mechanism. This review summarizes the promising strategies aimed at achieving selective production of diverse carbon-containing products, including CO, formate, hydrocarbons, alcohols, and organonitrogen compounds. These approaches involve the rational design of electrocatalysts and the construction of coupled electrocatalytic reaction systems. Moreover, this review presents the underlying reaction mechanisms, identifies the existing challenges, and highlights the prospects of the electrosynthesis processes. The aim is to offer valuable insights and guidance for future research on the electrocatalytic conversion of CO2 into carbon-containing products of enhanced value-added potential.

Insight into the Formation and Catalytic Mechanism of “CO Pool” during Electrocatalytic Conversion of CO2

The OC-CO coupling reaction, requiring pairs of *CO or *CHO intermediates absorbed on adjacent Cu sites, is the key elementary reaction during the electrocatalytic conversion of CO2 towards C2 products, where the harsh demand of adjacent *CO cause the transmission and preservation of CO species become the critical step of CO coupling reaction. Among the reported M-Cu (M=Ag, Au, Zn, etc....) tandem catalysts and Cu+-Cu sites, CO goes through the route of “generation-desorption-transmission-deeply reduction” over the catalytic surface. Despite the in-depth studies of the various site’s composition, morphological structures, and catalytic sites arrangement on Cu-based catalysts, the migratory manner on the electrode surface and the concentration and reactivity of CO in the double layer is still obscure, which are essential steps for CO spillover on the surface of Cu-based catalysts and further coupling reactions, as well as the underlying causes of the poor selectivity of CO/C2 products. At the same time, in situtechniques with temporal resolution are still lacking for probing the overflow and inter-diffusion of CO in the double layer.In this study, based on the rotating disk electrode, we developed an effective means for in situ monitoring of the transport and electrochemical properties of CO in the diffusion layer. Based on theoretical analysis of the electrochemical interface CO species transfer path and time-resolved RRDE techniques, we proved that most of the CO intermediates are favorable to transferred and then reserved in the diffusion layer, leading to an enhanced concentration of CO over equilibrium concentration, and finally benefitted the transmission and reactivity of CO species. By analyzing the reaction chain, combined with in situ ATR-SEIRAS monitor and theoretic calculation, the chemical potential was proved to be enhanced by introducing the “CO pool”, which could be resonated in the reaction chain, raised an increased entropy production and finally led to a resonance-enhanced concentration of by-intermediates, finally strengthening the activity of whole chain-system. Figure 1

SO2-Tolerant Electrocatalytic Reduction of CO2 from Simulated Industrial Flue Gas

The electrochemical reduction of CO2 using copper-based electrocatalysts offers a route to produce high-value multicarbon (C2+) products from renewable electricity (Nat. Catal. 4, 952-958 (2021); Nature 614, 262-269 (2023)). To date, the efficient electrocatalytic conversion of CO2 to multicarbon products has only been possible when using impurity-free CO2 sources, such as from direct air capture. The generation of such high-grade CO2 streams is expensive, accounting for almost half of the total energy required for both capture and electroreduction processes (Nat. Catal. 4, 952-958 (2021)). Conversely, capturing CO2 from point sources, such as industrial flue gas, is more efficient due to the higher concentration of CO2 in the feed. However, trace amounts of sulfur dioxide (10 ~ 400 ppm SO2) inherently present in these streams will significantly degrade the CO2 conversion process. All previous attempts to convert CO2 with SO2 present in the feed have resulted in immediate catalyst poisoning and an irreversible loss of CO2 conversion activity.In this study, we designed a modified catalyst layer to react a stream of dilute CO2 containing 400 ppm SO2 to multicarbon products with high stability and performance metrics that match or exceed those achieved with pure CO2 streams. Driven by density function theory and COMSOL simulations, we designed an ionomer:copper:polytetrafluoroethylene (PTFE) (ICP) electrode that features both hydrophobic and highly-charged hydrophilic domains to limit water adsorption and promote CO2 over SO2 transport near the electrochemically active sites. This deactivates the SO2 poisoning mechanism, thus enabling stable and efficient CO2 conversion (see figure). Our approach achieved a sustained C2+ Faradaic efficiency (FE) of 50% for the initial 160 hours at 100 mA cm-2.In order to improve the overall C2+ current efficiency (jC2+) towards industrial scales, we applied our strategy in high-surface-area copper electrodes. We achieved CO2 conversion in the presence of 400 ppm SO2 with a C2+ FE of 76% at a current density of 700 mA cm-2, surpassing what can be achieved in existing integrated CO2 capture-electrolysis systems that use pure CO2. Overall, our approach provides a fully 140-fold increase in performance (FEC2+ × jC2+) compared to the best prior CO2 conversion systems with added SO2 (Nat. Nanotechnol. doi: 10.1038/s41565-022-01286-y (2023); J. Am. Chem. Soc. 141, 9902-9909 (2019)). These findings represent an important advancement in the field of CO2 conversion and highlight the potential of our strategy for industrial-scale applications. Figure 1

Surface-Enhanced Raman Spectroscopy for Boosting Electrochemical CO2 Reduction on Amorphous-Surfaced Tin Oxide Supported by MXene.

Amorphous materials disrupt the intrinsic linear scalar dependence seen in their crystalline counterparts, typically exhibiting enhanced catalytic characteristics. Nevertheless, substantial obstacles remain in terms of boosting their stability, enhancing their conductivity, and elucidating distinct catalytic mechanisms. Herein, a core-shell catalyst, comprising a crystalline SnO2 core and an amorphous SnOx shell supported on MXene (denoted as SnO2@SnOx/MXene), was prepared utilizing hydrothermal and solution reduction methods. The SnO2@SnOx/MXene catalyst excels in the electrocatalytic conversion of CO2 to formate, yielding a Faradaic efficiency (FE) as high as 93% for formate production at -1.17 V vs RHE and demonstrating exceptional durability. Both density functional theory (DFT) calculations and experimental results indicate that the SnOx shell bolsters formate formation by fine-tuning the adsorption energy of the *OCHO intermediate. In SnO2@SnOx/MXene, MXene plays a vital role in enhancing the conductivity and stability of the amorphous shell and especially amplifying Raman signals of catalyst components. The ex/in situ surface-enhanced Raman scattering (SERS) application further confirms the formation of amorphous SnOx and further enables the direct detection of the formation of the intermediate species. This work provides the basis for the application of amorphous materials in practical electrocatalytic reduction of CO2 reduction.

Converting CO2 to multi-carbon products at >1 A/cm2 using gas diffusion electrode based on commercial materials via transfer process engineering

Cu-based gas diffusion electrodes for the electrocatalytic conversion of CO2 to high-value-added multi-carbon products is a promising technology. However, it is in urgent demand to develop high-efficiency electrode and electrolyzer to promote its poor reaction kinetics and product selectivity, which have seriously hindered its industrial application. Herein, the hydrophobicity property and the pore size distribution of microporous layer (MPL) and the hydrophobicity property of carbon fiber substrate (CFS) were studied to adjust electron transfer, CO2 transfer, and water transfer, which creates a microenvironment more suitable for the production of multi-carbon products. It is shown, by this strategy, ampere-level current density (1.36 A/cm2) is obtained using a gas diffusion electrode based entirely on commercially available materials, with partial current density of 0.697 A/cm2 and 0.885 A/cm2 for ethylene and C2+ products at −1.44V vs. RHE. Further characterizations show that the CO2 transfer via CFS and MPL to catalyst layer (CL) and water transfer determine CL local CO2 concentration and wettability to further influence the gas-liquid ratio and the coverage of *CO2, *H, and *CO on the catalyst surface to promote CC coupling and thus yield an optimal selectivity of C2+ products.

Plasma-surface-modified SnO2–CuCl nanocomposite for highly selective electrocatalytic CO2 conversion

Conversion of CO2 into useful chemicals via electrochemical methods is a promising approach for mitigating global CO2 emissions and transiting towards green chemical production. In this work, a tin oxide-copper chloride (SnO2–CuCl) nanocomposite catalyst for efficient CO2 conversion is developed using low-temperature atmospheric-pressure plasmas. The SnO2–CuCl catalyst which acquired a unique structure subjected to the dielectric barrier discharge (DBD) plasma (SnO2–CuCl-DBD), effectively inhibits the hydrogen evolution reaction (HER) in the electrocatalytic process. Compared with the untreated SnO2–CuCl sample, the H2 generation efficiency of the SnO2–CuCl-DBD electrocatalyst decreased from 9.79 to 3.41 %. The demonstrated efficiency of SnO2–CuCl-DBD catalyst for conversion of CO2 to C1 products (formate and CO) is 94.37 % at 1.8 V (vs Ag/AgCl), which is very competitive to the reported state-of-the-art catalyst. The outcomes of this research provide a new practical surface science approach for engineering advanced electrocatalysts for effective conversion of CO2 into value-added chemical products.

1.42-fold enhancement of formate selectivity by linker conversion on the Zn-based metal organic framework catalyst

Electro-reduction of carbon dioxide (ERCO2) is considered an effective method to alleviate the greenhouse effect and produce value-added chemicals. Achieving the dominant selectivity of Zn-based catalysts for formate remains a challenge. In this article, the ZnIn-E12 catalyst is successfully prepared by solvent assisted ligand exchange (SALE) method to convert organic ligands, achieving a Faradaic efficiency of 72.28% for formate at −1.26 V vs. RHE (VRHE), which is 1.42 times higher than the original catalyst. Evidence shows that the successful conversion of organic ligands can transform the catalyst from the original large size polyhedron to cross-linked network of particles with a diameter of about 30 nm. The increased specific surface area can expose more active sites and facilitate the electrocatalytic conversion of CO2 to formate. This work is expected to provide inspiration for the regulation of formate selectivity and catalyst size in Zn-based catalysts.