Abstract:

To solve the excessive emission of CO₂ caused by the excessive use of fossil fuels and the corresponding environmental problems, such as the greenhouse effect and climate warming, electrocatalytic CO₂ reduction to liquid fuel with high selectivity is of huge significance for energy conversion and storge. Indium has been considered as a promising and attractive metal for the reduction of CO₂ to formate. However, the current issues, such as low selectivity and current activity, largely limit the industrial application for electrocatalytic CO₂ reduction, the design optimization of the catalyst structure and composition is extremely important. Herein, we develop a facile strategy to regulate surface In-O of In@InO_x core-shell nanoparticles and explore the structure-performance relationship for efficient CO₂-to-formate conversion though air calcination and subsequent in situ electrochemical reconstruction, discovering that the surface In-O is beneficial to stabilize the CO₂ intermediate and generate formate. The optimized AC-In@InO_x-CNT catalyst exhibits a C₁ selectivity up to 98% and a formate selectivity of 94% as well as a high partial formate current density of 32.6 mA cm^-2. Furthermore, the catalyst presents an excellent stability for over 25 h with a limited activity decay, outperforming the previously reported In-based catalysts. These insights may open up opportunities for exploiting new efficient catalysts by manipulating their surface.

Key words: In-O content, Core-shell nanoparticles, CO₂ reduction, Formate, Electrocatalysis