Defect engineered SnO2 nanoparticles enable strong CO2 chemisorption toward efficient electroconversion to formate

Abstract

Oxygen vacancy (O_v) engineering of SnO₂ electrocatalysts plays a crucial role in realizing efficient CO₂ electroreduction (CO₂RR) into formate. Herein, we demonstrate the rational synthesis of highly dispersed SnO₂ nanoparticle electrocatalysts with an ultrahigh O_v content of up to 25.1% by a thermally induced strategy. The high O_v content greatly improves the intrinsic conductivity and remarkably enhances the chemisorption capacity to CO₂, thus boosting the catalytic activity and reaction kinetics of CO₂ electroconversion into formate. These advantages make the O_v-engineered SnO₂ electrocatalysts exhibit both a high Faraday efficiency (FE) of nearly 90% and a superior cathodic energy efficiency of above 60% to produce formate in a wide current range from 100 to 400 mA cm⁻² in a flow cell. A commercially required current of 200 mA cm⁻² can be obtained at only 2.8 V in a full cell. The present O_v engineering strategy exhibits the possibility for the design and construction of high-activity oxide-based electrocatalysts.