Elevating the p-band centre of SnO2 nanosheets through W incorporation for promoting CO2 electroreduction

Abstract

SnO₂ is one of the most promising catalysts for CO₂ electroreduction. However, the intrinsic low electrical conductivity and weak CO₂ adsorption and activation capability have rendered the reaction kinetically sluggish and inefficient. To surmount these hurdles, herein, W was incorporated into SnO₂ nanosheets to modulate the electronic structures. Compared with pristine SnO₂, the p-band centre of W-doped SnO₂ was elevated towards the Fermi level, accompanied by the reduction in the band gap and work function. As a result, both the CO₂ adsorption and the electron transfer process were promoted, thus lowering the activation energy barrier for CO₂ reduction. Benefitting from these, a maximum faradaic efficiency of 87.8% was achieved for HCOOH at −0.9 V vs. the RHE. Meanwhile, the current density and energy efficiency approached 20.92 mA cm⁻² and 60%, respectively. Such performances could sustain for 14 h without obvious fading and exceeded pristine SnO₂ and most reported Sn-based catalysts. Tafel slope and reaction order analyses further suggested that the reaction proceeded following a stepwise electron–proton transfer pathway with the formation of CO₂˙⁻ as the rate determining step. This work demonstrated the effectiveness of electronic structure tuning in promoting the catalytic performances of p-block metal oxides and contributed to the development of efficient catalysts for sustainable energy conversion and carbon neutrality.