Correlating the crystal structure and facet of indium oxides with their activities for CO2 electroreduction

•The correlation between the phase and facet of Indium oxides with their activity of CO2 electroreduction has been established.•The cubic phase is more active for CO2 electroreduction than the hexagonal phase, and cubic (111) surface shows the highest intrinsic activity.•The cubic In2O3 nanosheets (C-In2O3-NS) with predominately exposed (111) surface has shown a significantly enhanced activity and formate selectivity than other In2O3 catalyststs with different phases or surfaces.