Self-Healing Indium Sulfide Catalyst for Efficient and Robust Electrocatalytic CO2 Conversion.

The reduction-reconstruction of the catalyst under negative bias has been identified as a significant rationale underlying the performance degradation of the electrocatalytic CO2 reduction reaction (CO2RR). Screening catalysts with stable phases and robust crystal structures appears to be a feasible approach to counteract the reduction corrosion. In this work, with the guidance of computational predictions, a tetragonal phase In2S3 electrocatalyst is designed through a self-healing strategy for the conversion of CO2 to formate. Remarkably, In2S3 exhibits superior stability for over 200 h at a current density of ∼210 mA cm-2, with a persistent formate faradaic efficiency of ∼97%. A series of in situ spectroscopic measurements confirm that In2S3 maintains the structural and valence state integrity throughout the reaction. Combined with density functional theory calculations, the performance enhancement mechanism and self-healing principle of In2S3 are clearly elucidated. This work provides a novel perspective for the design of highly efficient and stable CO2RR electrocatalysts.