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

Tuning surface electron transfer process by oxygen (O)-vacancy engineering is an efficient strategy to develop enhanced catalysts for CO electroreduction (CO ER). Herein, a series of distinct InO NRs with different numbers of O-vacancies, namely, pristine (P-InO ), low vacancy (O-InO ) and high-vacancy (H-InO ) NRs, have been prepared by simple thermal treatments. The H-InO 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 and O-InO NRs. The H-InO 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 NRs, which optimizes CO adsorption/activation and facilitates electron transfer for efficient CO ER.