Selective electrocatalytic reduction of CO2 to formate via carbon-shell-encapsulated In2O3 nanoparticles/graphene nanohybrids

Constructing nanohybrids with a synergistic effect using multi-components and specific micro/nanostructures can significantly enhance their electrocatalytic activity. In this work, we fabricated an In2O3⊃[email protected] nanohybrid, in which In2O3 nanoparticles (NPs) were encapsulated by an N-doped carbon (NC) shell and supported on graphene. The multi-components in In2O3⊃[email protected] synergistically optimize the structural and electronic properties of the material. The particle size and dispersion of In2O3 NPs were optimized owing to the separation effect of the amorphous NC shell and graphene support. This separation effect exposes more number of active sites for the electrochemical reaction. Abundant oxygen vacancies exist in In2O3, leading to a stronger ability for the adsorption and activation of CO2. The NC shell inhibits the direct contact between the electrolyte and In2O3, which significantly suppresses competitive H2 evolution. The charge transfer during the electrocatalysis process is also effectively enhanced due to the carbon components. The synergistic effect of multi-components in the In2O3⊃[email protected] sample results in a significantly improved CO2 reduction reaction performance with a high HCOO– Faradic efficiency (FE) of 91.2% and a current density of 40.38 mA cm–2 at –0.8 V obtained using a flow cell. The present work demonstrates that rationally designing nanohybrids with multifunctional components is an effective strategy for optimizing the structural and electrocatalytic properties of materials for energy conversion.