Oxygen Vacancies in Amorphous InOx Nanoribbons Enhance CO2 Adsorption and Activation for CO2 Electroreduction

Abstract Tuning surface electron transfer process by oxygen (O)‐vacancy engineering is an efficient strategy to develop enhanced catalysts for CO 2 electroreduction (CO 2 ER). Herein, a series of distinct InO x NRs with different numbers of O‐vacancies, namely, pristine (P‐InO x ), low vacancy (O‐InO x ) and high‐vacancy (H‐InO x ) NRs, have been prepared by simple thermal treatments. The H‐InO x NRs show enhanced performance with a best formic acid (HCOOH) selectivity of up to 91.7 % as well as high HCOOH partial current density over a wide range of potentials, largely outperforming those of the P‐InO x and O‐InO x NRs. The H‐InO x NRs are more durable and have a limited activity decay after continuous operating for more than 20 h. The improved performance is attributable to the abundant O‐vacancies in the amorphous H‐InO x NRs, which optimizes CO 2 adsorption/activation and facilitates electron transfer for efficient CO 2 ER.