Oxygen Vacancies in Amorphous InOx 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 InOx NRs with different numbers of O-vacancies, namely, pristine (P-InOx ), low vacancy (O-InOx ) and high-vacancy (H-InOx ) NRs, have been prepared by simple thermal treatments. The H-InOx 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-InOx and O-InOx NRs. The H-InOx 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-InOx NRs, which optimizes CO2 adsorption/activation and facilitates electron transfer for efficient CO2 ER.