Oxygen Vacancies in Amorphous InO x Nanoribbons Enhance CO 2 Adsorption and Activation for CO 2 Electroreduction

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.