Interface Regulation Of Copper-based Nanostructures For Electrocatalytic CO₂ Reduction

Global CO2 concentrations peaked in 2030,which have greatly sharpened the "greenhouse effect",and the issue of climate change has become prominent.Electrochemical catalytic reduction of CO2 into hydrocarbons,alcohols and other high energy density products is an important link to realize artificial carbon cycle and a vital way to ease the depletion of fossil fuels and the "greenhouse effect".Copper is currently the only metal that can reduce CO2 to C2+products.At present,the regulation of copper-based compounds mainly focuses on morphology,size,crystal plane and valence state,but the catalytic mechanism of producing C2+products has not been clearly explained.Therefore,how to deeply understand the reaction mechanism of CO2 reduction on copper-based catalysts,design and build efficient catalysts and solve the problem of gas diffusion are crucial to promote the selectivity of electrocatalytic CO2 reduction products.Based on this,this topic is dedicated to the design of copper-based catalysts and study of reaction pathways,mainly explored two aspects of the content,one is the catalyst interface construction and regulation;On the other hand is effective control of the adsorption mode of intermediates at the interface.(1)Enriched-Cu2O/Cu interfaces were constructed in situ on the Cu2O surface by square wave potential method,which improved the selectivity of C2+products,especially ethylene.In order to solve the problems of unclear reaction mechanism and poor product selectivity of copper-based catalysts,the interfacial of Cu+ and Cu0 on the catalyst surface was used to synergistic adsorb*CO intermediates,which realized the selective regulation of reaction intermediates,reduced the reaction energy barrier of C-C coupling,promoted the dissociation of H2O molecules to produce active H protons and showed excellent selectivity of C2+products.(2)Enriched-Cu3N/Cu interfaces were constructed on the Cu3N surface by square wave potential method,which improved the selectivity of C2+products,especially ethylene.Aimed at Cu+in the reaction process of the poor stability,the introduction of nitrogen element to improve the stability of Cu+,because of a nitrogen atom is easy to get electronic,makes the copper atoms in the electrolytic process to maintain high valence state and stable.Meanwhile,the copper of catalyst surface is positively charged with zero-valent copper with interface synergy,which realized the selectivity regulation of the reaction intermediates.(3)Cu2(OH)2CO3/CuO with high-valence interfaces was prepared by in-situ decomposition of basic copper carbonate under CO2 induced by high temperature calcination,and the selectivity of the product was changed from ethylene to ethanol.Synthesis in the atmosphere of feed gas is conducive to the adsorption of CO2 gas on the surface of the catalyst,providing sufficient CO2 supply.Meanwhile,the interfaces changed the interatomic distance of Cu-Cu and produced more alkaline sites,,improving the competitiveness of ethanol products.