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.