Highly active platinum decorated BiVO4 nanosheet/TiO2 nanobelt heterojunction for photocatalytic CO2 reduction

A series of BiVO4/TiO2 photocatalysts with different BiVO4 to TiO2 molar ratios (1, 1/2, 1/3, and 1/4) was synthesized and evaluated for the photocatalytic CO2 reduction. The crystalline structure, morphological characteristics, and optical properties of the as-prepared samples were investigated using XRD, FESEM, N2-physisorption, Raman spectroscopy, TPD, PL, and DRS. The results showed that the fabrication of a heterojunction structure between BiVO4 and TiO2 semiconductors could improve the optical properties and electron-hole separation efficiency. The CO2 adsorption capacity of TiO2 increased with the loading of BiVO4 on TiO2. The composite photocatalysts exhibited a much higher photocatalytic performance than the pure BiVO4 and TiO2 photocatalysts because of the formation of a heterojunction structure between the BiVO4 nanosheets and TiO2 nanobelts. The BVT2 sample with a 1/2 molar ratio of BiVO4 to TiO2 showed the maximum CH4 production (28 mu mol/g) in 8 h, which was approximately seven times higher than that of the pure TiO2 (4 mu mol/g). Loading Pt on the BVT2 surface significantly enhanced the photocatalytic performance and methane yield (39.7 mu mol/g). Enhanced photocatalytic performance of the Pt@BVT2 sample corresponded to enhanced CO2 adsorption efficiency and reduced recombination rate of photoinduced electron-holes by the deposition of Pt particles on BVT2.