Construction of unique two-dimensional MoS2–TiO2 hybrid nanojunctions: MoS2 as a promising cost-effective cocatalyst toward improved photocatalytic reduction of CO2 to methanol

Abstract

Two-dimensional MoS₂ nanosheets were in situ grown on TiO₂ nanosheets to form two-dimensional (2D) hybrid nanojunctions, with which MoS₂ nanosheets compactly contact with TiO₂ to increase the interfacial area. MoS₂ was identified as a promising cost-effective substitute for noble metal cocatalysts such as Pt, Au, and Ag, and shows superior activity and selectivity for reducing CO₂ to CH₃OH in aqueous solution to these metal cocatalysts under UV-vis light irradiation. The photo-luminescence (PL) spectra and transient time-resolved PL decay measurements reveal that the fast electron transfer from TiO₂ to MoS₂ can minimize charge recombination losses to improve the conversion efficiency of photoreduction. It reveals that Mo-terminated edges of MoS₂ nanosheets possess the metallic character and a high d-electron density, and the Mo cation sites may benefit the stabilization of CH_xO_y intermediates via electrostatic attraction to enhance the CH₃OH formation from the reduction of CO₂ in aqueous solution.