Construction of unique two-dimensional MoS 2 -TiO 2 hybrid nanojunctions: MoS 2 as a promising cost-effective cocatalyst toward improved photocatalytic reduction of CO 2 to methanol.

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 CHxOy intermediates via electrostatic attraction to enhance the CH3OH formation from the reduction of CO2 in aqueous solution.