Defective Indium/Indium Oxide Heterostructures for\nHighly Selective Carbon Dioxide Electrocatalysis

Abstract

Electrochemical CO₂ reduction to fuels and chemicals\nis a promising approach for CO₂ utilization. Developing\nhighly active, selective, and cost-effective electrocatalysts is the\nkey to the large-scale application of this technology. Here, we report\nthat defective indium/indium oxide heterostructures selectively catalyze\nCO₂ electroreduction into C₁ products in a broad\npotential range from −0.7 to −1.2 V vs RHE in aqueous\nmedia with the faradaic efficiency approaching 100%. This electrocatalyst\nenables an efficient CO₂-to-formate conversion with excellent\nselectivity (up to 93%), activity (up to 50.8 mA cm^–2), and durability (>25 h). The collaboration between metallic\nIn\nand In oxide of the heterostructures attributes to the boosted electrochemical\nCO₂ reduction: Metallic In mainly facilitates formate production,\nwhile In oxide suppresses the competing hydrogen evolution reaction.\nThis study highlights the integration of different functional components/defects\ninto heterostructures as an effective strategy for enhancing CO₂ electrocatalysis.