Nano Ag-Decorated MoS2 Nanosheets from 1T to 2H Phase Conversion for Photocatalytically Reducing CO2 to Methanol

Exfoliated MoS2 with a 2H phase has unique semiconductor properties and is used for the photocatalytic reduction of CO2 herein. Flower-like MoS2 nanosheets are synthesized by the hydrothermal method and are used to fabricate an enlarged lamellar structure with a 1T phase of MoS2 in the presence of lithium ions under sonication; the 1T-to-2H phase conversion of MoS2 is successfully realized in o-dichlorobenzene solution. To improve the photocatalytic performance, Ag nanoparticles are combined with the as-prepared 2H-MoS2 to form the Schottky knot. The obtained Ag/2H-MoS2 composites are characterized and evaluated for their compositions, morphologies, microstructures, and photocatalytic activities in the reduction of CO2 to methanol. Herein, it was found that the electron and hole excited by light on the composites are more effectively separated through deposited nano Ag, and their photocatalytic ability of reducing CO2 to methanol is promoted simultaneously. The highest yield of methanol up to 365.08 mu mol(-1) g(-1) h(-1) appears at 20 wt% Ag on MoS2. Finally, a reasonable photocatalytic reaction mechanism is proposed.