Dual active sites fabricated through atomic layer deposition of TiO2 on MoS2 nanosheet arrays for highly efficient electroreduction of CO2 to ethanol

Abstract

Electrochemical reduction of CO₂ to ethanol through renewable electricity is highly desirable but still challenging. Here, we demonstrated that TiO₂/MoS₂ nanosheet arrays synthesized through atomic layer deposition (ALD) of TiO₂ on the surfaces of MoS₂ nanosheet arrays enabled the electrochemical CO₂ reduction reaction (CO₂RR) toward ethanol. As a result, 50% faradaic efficiency (FE) for ethanol was achieved over the obtained electrocatalyst at only −0.60 V versus the reversible hydrogen electrode (RHE) in CO₂-saturated 0.5 M KHCO₃ aqueous solution, which ranks as the best electrocatalysts for the CO₂RR to ethanol. The experimental results and theoretical calculations showed that Mo and Ti dual active sites formed on the interfaces of TiO₂ and MoS₂ could adjust CO binding energy and promote the CO–CO coupling reaction and its subsequent transformation. A new regulatory mechanism of the CO coupling reaction and the possible reaction path were proposed based on experimental results and density functional theory (DFT) calculations.