Wavy SnO2 catalyzed simultaneous reinforcement of carbon dioxide adsorption and activation towards electrochemical conversion of CO2 to HCOOH

We report the preparation of an “all in one” wavy SnO2 with abundant oxygen vacancies, grain boundaries and low-coordinated active sites (such as edge and corner sites), which simultaneously intensifies the adsorption and activation of CO2, facilitates electron transfer, therefore, improves the efficiency of CO2 reduction reaction (CO2RR). [Display omitted] •Wavy SnO2 was used to electrochemical converse carbon dioxide into HCOOH for the first time.•Wavy SnO2 exhibits enhanced adsorption and activation ability of CO2 molecular and CO2•- intermediate.•Wavy SnO2 with abundant oxygen vacancies, grain boundaries and low-coordinated active sites (such as edge and corner sites) is the reason for the enhanced CO2RR activity and selectivity.•Wavy SnO2 shows a maximum FEHCOOH (87.4%) and EEHCOOH (57.5%) at -1.0 V vs. RHE.•Wavy SnO2 enjoys the lower onset overpotential and higher HCOOH partial current density than the nanoparticle SnO2. The tin oxide (SnO2) based materials have emerged as one of the most promising candidates to highly electrolyze the carbon dioxide (CO2) and produce formic acid. However, it still cannot meet the requirement for practical application because a substantial overpotential is needed to achieve a high HCOOH Faraday efficiency (FE) along with a large current density. In this work, we report the preparation of an “all in one” wavy SnO2 having abundant oxygen vacancies, grain boundaries and low-coordinated active sites (such as edge and corner sites) by a facile yet simple one-pot hydrothermal strategy, which simultaneously intensifies the adsorption and activation of CO2, facilitates electron transfer and thus, improves the efficiency of CO2 reduction reaction (CO2RR). Importantly, this study demonstrates a wavy SnO2 (NW-SnO2) with optimized surface structure for the significantly enhanced electrocatalytic reduction of CO2 to HCOOH with maximum FEHCOOH = 87.4% and EEHCOOH = 57.5% at −1.0 vs VRHE. The synthesizing process reported herein is superior to a number of the current SnO2 based electrocatalysts since it is much easier, more cost effective and benign, an apparent advantage in terms of its future large scale of applications. This study could be extended to much abroad applications and serves as a guide to synthesize other metallic oxide based catalysts for CO2RR by tuning surface structure.