The Construction And Performance Of Copper-based Heterostructure Catalysts For Electrocatalytic Carbon Dioxide Reduction

The depletion of natural resources are extremely serious problems due to massive consumption of fossil fuels and the greenhouse effect caused by excessive emission of greenhouse gases,mainly carbon dioxide（CO₂）.At present,electrocatalytic carbon dioxide reduction（ECR）reaction has far-reaching significance as one of the effective solutions.Clean renewable energy can be used as electricity in electrocatalysis to reduce CO₂.At the same time,the generated carbon products can be realized in energy recycling.However,ECR process is relatively complex,with a wide range of products and a variety of reaction pathways.Therefore,it is still the focus to find suitable catalysts and explore the mechanisms to achieve high efficient ECR performances.The ECR performance can be improved by optimizing the active site environment with some reasonable methods.Copper-based catalysts possess the capability to generate a diverse array of products,including high-value ones.Nevertheless,conventional copper-based catalysts are still subject to certain limitations such as inadequate selectivity,sluggish reaction kinetics,challenging production of profound transformation products and insufficient stability.In view of the above research status,this paper has studied copper-based heterostructure catalysts,and utilized the synergistic effects（such as regulating electronic structure,tandem mechanism and the enhancement of CO₂adsorption）to promote the ECR preformances.By reasonable material design,preparation and testing,the mechanisms of the copper-based heterostructure catalysts in the electrocatalytic carbon dioxide reduction reaction were explored,and the performances of the catalysts were significantly improved.The specific research contents and conclusions are as follows:1.We report that highly efficient CO₂electroreduction to methane（CH₄）is achieved over a precisely controlled Cu-Zn O heterointerface system,delivering a superior activity with the Faradaic efficiency up to 72.4%at-0.7 V vs.RHE.Experimental phenomenons and theoretical calculations confirm the high CO₂to CH₄selective is derived from the interfacial synergistic effect between Cu and Zn O nanostructure.DFT calculation shows that the electronic structure of interfacial Cu sites is significantly modulated by Zn O,resulting in moderate adsorption energies of*COOH and*CHO intermediates on Cu sites,and in turn,promoting the conversion from CO₂to CH₄.This work unravels the strong dependence of CO₂reduction selectivity on the heterointerfaces,and provides a platform for designing highly selective electrochemical catalysts.The efficiency of generating deep conversion products has been enhanced.2.We report a self-supporting bimetallic porous heterogeneous indium/copper structure synthesized with a eutectic gallium-indium（EGa In）with a copper substrate.This nanoporous copper-indium heterostructure catalyst exhibits excellent performance for carbon dioxide reduction to syngas.The ratio of H₂:CO is tuneable from 0.47 to 2.0 by changing working potentials.The catalyst is very stable,showing96%maintenance of the current density after a 70 h continuous test.Density functional theory calculations reveal that the indium/copper interface induces charge redistribution within copper surface,leading to the formation of two distinct active sites,Cu^δand Cu⁰and enabling high performance generation of both CO and H₂.The reaction kinetics is optimized.This work provides a new strategy for obtaining self-supporting nanoporous metal electrode catalysts.3.By means of thermal decomposition of nitrate on the surface of copper foam substrate,different heterostructures of Cu₂O-Ce O₂catalysts were designed and successfully synthesized.The utilization of a tandem mechanism facilitates the formation of intermediates and subsequent coupling reactions.The effects on the transformation from CO₂to multi-carbon products were investigated.The experimental and theoretical calculations show that catalysts have similar interfaces but exhibit different ECR properties,indicating that different types of heterostructures have a significant impact on the performance of ECR.And the reason is due to the major exposed structures,which affects the tandem mechanism of generating multi-carbon products.This work provides a foundation for designing efficient tandem catalysts in the future.4.We report an in-situ synthesis of metal-organic frameworks（MOF）encapsulated bimetallic nanoparticles by etching nickel-copper alloy nanoparticles without additional metal precursors.The nickel-copper nanoparticles serve as the metal precursor sources and are encapsulated into metal organic frameworks to enhance the catalytic performances for ECR,which can be attributed to the synergistic effect.Also,the catalyst shows excellent OER performance and stability.By elevating the CO₂concentration in proximity to the active sites,this work has overcome the poor CO₂adsorption capability of traditional materials.As a result,it significantly enhances current density and selectivity,offering a novel approach for designing superior adsorption-enhanced catalysts.