Surface Dual-Modification of Nano-Cu2o for Controlling CO2 Electrochemical Reduction to Ethylene and Syngas

Abstract

Carbon dioxide (CO2) is an important substance in the natural carbon cycle, and the gradual increase of CO2 emissions has exceeded the amount that can be absorbed by the nature, which has brought a huge impact on climate conditions and ecological environment. In addition, CO2 is an important C1 resource, and it is of great significance to convert it by electrochemical methods to important chemical raw materials (such as ethylene and syngas) needed for human life. Cu2O is an ideal electrocatalyst due to its relatively low cost and unique product selectivity, as well as the abundant Cu reserves on the earth. However, there is still a lack of systematic studies on the improvement of the C2H4 selectivity of Cu2O-based catalyst and the regulation of product selectivity.In this work, different exposed facet nano-Cu2O were obtained by induction of reducing agent. Combined with in-situ characterization and theoretical calculation, it was found that the terrace × step structure (332) crystal surface can significantly reduce the free energy of C-C coupling process, and greatly improve the selectivity of electrochemical CO2 reduction to C2H4, which is the highest value (74.1%) obtained by Cu2O based catalyst with neutral electrolyte.Subsequently, the ZIF-8 shell is introduced in-situ on the surface of Cu2O nanoparticles. The coated ZIF-8 shell effectively regulates the hydrophilic and hydrophobic environment of the material, and provides a material exchange channel for reactants and product molecules simultaneously, which promote the desorption of CO molecules and improve the adsorption of CO2, realizing the switch of product from C2H4 to syngas.In carbon dioxide reduction, it is an important strategy to modify the surface of metal/metal oxide by interface engineering to regulate the microenvironment at the reaction interface. In this paper, from the aspects of material design, synthesis and regulation of reaction products, the great advantages of facet structure and MOFs for improving the stability and activity of catalyst are demonstrated. Combined with in situ characterization and theoretical calculation, a new idea is provided for the design of efficient carbon dioxide electroreduction catalyst in the future. Figure 1