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

Tuning surface electron transfer process by oxygen (O)-vacancy engineering is an efficient strategy to develop enhanced catalysts for CO₂ electroreduction (CO₂ 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 CO₂ adsorption/activation and facilitates electron transfer for efficient CO₂ ER.