Elevating the p-band centre of SnO nanosheets through W incorporation for promoting CO electroreduction.

SnO is one of the most promising catalysts for CO electroreduction. However, the intrinsic low electrical conductivity and weak CO adsorption and activation capability have rendered the reaction kinetically sluggish and inefficient. To surmount these hurdles, herein, W was incorporated into SnO nanosheets to modulate the electronic structures. Compared with pristine SnO, the p-band centre of W-doped SnO was elevated towards the Fermi level, accompanied by the reduction in the band gap and work function. As a result, both the CO adsorption and the electron transfer process were promoted, thus lowering the activation energy barrier for CO reduction. Benefitting from these, a maximum faradaic efficiency of 87.8% was achieved for HCOOH at -0.9 V the RHE. Meanwhile, the current density and energy efficiency approached 20.92 mA cm and 60%, respectively. Such performances could sustain for 14 h without obvious fading and exceeded pristine SnO 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 CO˙ 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.