Study Of The Electrocatalytic Reduction Of Carbon Dioxide To Multi-carbon Products By Copper-silver Tandem Catalyst

With the increase of human activities and global industrialization,carbon dioxide emissions are rising,causing various environmental problems such as the greenhouse effect,which has garned significant attention from various countries.Due to social development and industrial production,it is challenging to change the energy mix in a short period,Therefore,it is urgent to explore an efficient,stable,economical and reliable method to reduce CO2 emissions.Obtaining continuous and stable electric power driven by renewable energy and reducing carbon dioxide to multi-carbon products through electrocatalysis is a promising strategy for energy storage and global warming mitigation.However,breaking the high energy barrier of C-C coupling to obtain high activity and selecti vity of a single product(such as ethanol)remains a significant challenge.This paper aims to synthesize copper-silver-based composite catalysts with simple,economical preparation methods from multiple perspectives,such as size,morphology,carrier,and organic ligand effects.The goal is to improve selectivity and activity for specific products,reduce overpotential,and improve catalyst stability.Firstly,this paper explored the synthesis of silver-based catalysts with different sizes and carriers,screening for silver nanoparticles(Ag NPs)that are favorable for producing single-carbon(C1)intermediates as catalysts in the pre-catalysis stage of tandem catalysis.On this basis,various methods such as in-situ growth and organic ligand effects were attempted to control the distribution of Cu active sites on Ag NPs.By optimizing this spatial distribution structure,a more abundant copper-silver interface was created to fully utilize locally enriched carbon monoxide(CO)intermediates and induce specific product pathways in CO2 reduction.Based on the previous study,this paper explored the synthesis of an organic binuclear copper precursor and utilized the immiscibility of copper and silver to induce atomic rearrangement during annealing.This led to the construction of a multi-level hierarchical interface in the core-shell catalyst obtained.The atomic interaction between Ag and Cu increased the electrochemical surface area and accelerated the charge kinetics,resulting in unprecedented electrocatalytic performance.The catalyst exhibited a Faraday efficiency of 80.2%for the C2+product at-1.0 V(relative to the reversible hydrogen electrode)potential,including 52.6%for ethanol,and a total current density of～320 mA cm-2.In addition,the catalyst was able to operate continuously for nearly 60 h while maintaining stable selectivity.Finally,a mechanistic study shows that local CO intermediates preferentially accumulate on the core and then migrate to the continuous Cu surface,and that the C-C coupling energy favors ethanol production.This work emphasizes the new design principles of interface engineering of advanced series electrocatalysts and is expected to provide a new idea and strategy for the design of catalysts for carbon dioxide electrocatalytic reduction to multicarbon products.