Mn-doped atomic SnO2 layers for highly efficient CO2 electrochemical reduction

Abstract

An efficient catalyst is the key to the application of the electrocatalytic CO₂ reduction reaction (CO₂RR). Herein, we report a facile in situ gas induced growth strategy to synthesize Mn-doped SnO₂ (TMO) with a thickness of 3–4 atomic layers for highly efficient CO₂ electroreduction. Compared with commercial SnO₂, TMO (with 11.86 wt% Mn) exhibits enhanced performance with a higher current density (∼21.2 mA cm⁻²), higher faradaic efficiency (∼85%) and lower overpotential (240 mV) for formic acid formation. The total faradaic efficiency for CO₂ conversion reaches ∼91.6%. X-ray fine structure and density functional theory studies reveal that the ultrathin nanostructure not only features a shrunken energy gap for electron transfer but also exposes more surface active sites. Meanwhile, Mn doping modulates the electronic configuration of SnO₂ and generates a large amount of oxygen vacancies. The designed ultrathin structure and Mn doping remarkably decreased the energy barrier of electron transportation on the TMO surface during the CO₂RR.