Pt-Cu@Bi 2 MoO 6 /TiO 2 Photocatalyst for CO 2 Reduction.

Bi 2 MoO 6 /TiO 2 heterojunction photocatalysts were constructed by depositing Bi 2 MoO 6 nanosheets on TiO 2 nanobelts' surface using a solvothermal method, and the surface of the optimum Bi 2 MoO 6 /TiO 2 composite was decorated with copper and/or platinum nanoparticles. The synthesized samples were investigated for the CO 2 photocatalytic reduction. The structural and optical properties of synthesized photocatalysts were characterized by XRD, FESEM, EDX, N 2 -physisorption, Raman, TPD-CO 2 , DRS, and PL analysis. The Bi 2 MoO 6 /TiO 2 composite with different molar ratios of Bi 2 MoO 6 to TiO 2 (1, 1/2, 1/3, 1/4, 1/5, and 1/6) showed enhanced photocatalytic activity compared to pure Bi 2 MoO 6 and TiO 2 . In comparison to bulk Bi 2 MoO 6 and TiO 2 , the formation of a heterojunction between Bi 2 MoO 6 and TiO 2 leads to enhanced CO 2 adsorption capacity. The enhanced performance of composites can be ascribed to the improved efficiency of light harvesting in the visible light range and suppressing charge recombination. The composite photocatalytic activity indicated that the ratio of Bi 2 MoO 6 to TiO 2 in the composite samples influenced the photocatalytic performance. The Bi 2 MoO 6 /TiO 2 composite with 1/4 molar ratio had the best performance in 8 h (36.4 μmol/g cat ), which was about 10 and 3 times higher than TiO 2 and Bi 2 MoO 6 photocatalysts, respectively. Under UV-visible light irradiation, the Pt-Cu@BMT4 sample produced the highest amount of methane (83.6 μmol/g cat ) during CO 2 photoreduction. During four irradiation cycles, the Pt-Cu@BMT4 sample exhibited superior stability with less than 5% decrease in methane production.