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, ½, ⅓, and ¼) 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 ½ molar ratio of BiVO4 to TiO2 showed the maximum CH4 production (28 µmol/g) in 8 h, which was approximately seven times higher than that of the pure TiO2 (4 µmol/g). Loading Pt on the BVT2 surface significantly enhanced the photocatalytic performance and methane yield (39.7 µmol/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.