Correlating the crystal structure and facet of indium oxides with their activities for CO_(2)electroreduction

Constructing structure-function relationships is critical for the rational design and development of efficient catalysts for CO_(2) electroreduction reaction(CO_(2)RR).In_(2)O_(3) is well-known for its specific ability to produce formic acid.However,how the crystal phase and surface affect the CO_(2)RR activity is still unclear,making it difficult to further improve the intrinsic activity and screen for the most active structure.In this work,cubic and hexagonal In_(2)O_(3) with different stable surfaces((111)and(110)for cubic,(120)and(104)for hexagonal)are investigated for CO_(2)RR.Theoretical results demonstrate that the adsorption of reactants on cubic In_(2)O_(3) is stronger than that on hexagonal In_(2)O_(3),with the cubic(111)surface being the most active for CO_(2)RR.In experiments,synthesized cubic In_(2)O_(3) nanosheets with predominantly exposed(111)surfaces exhibited a high HCOO^(-)Faradaic efficiency(87.5%)and HCOO^(–)current density(–16.7 mA cm^(-2))at–0.9 V vs RHE.In addition,an aqueous Zn-CO_(2) battery based on a cubic In2O3 cathode was assembled.Our work correlates the phases and surfaces with the CO_(2)RR activity,and provides a fundamental understanding of the structure-function relationship of In_(2)O_(3),thereby contributing to further improvements in its CO_(2)RR activity.Moreover,the results provide a principle for the directional preparation of materials with optimal phases and surfaces for efficient electrocatalysis.