Boosting the photocatalytic ability of hybrid biVO4-TiO2 heterostructure nanocomposites for H2 production by reduced graphene oxide (rGO)

Fabricating heterostructures has been recognized as an effective strategy to improve visible-light photocatalytic H-2 production performance. Therefore, a simple approach based on combining template-assisted liquidphase deposition and hydrothermal techniques was introduced to synthesize BiVO4-TiO2/reduced graphene oxide (rGO) heterostructure nanocomposites. The ternary hetero-nanostructures were composed of TiO2 nanotubes, with an average diameter of 100 nm and tens micrometers in length, BiVO4 nanoparticles and various amounts of rGO nanosheets. The highest photocatalytic H-2 production rate of 1427.1 mu mol.h(-1) g(-1) with an apparent quantum yield of 6.4% at 420 nm was achieved at optimum rGO content (3 wt.%) under visible-light irradiation, which was 2.5 and 1.5 times higher than that of TiO2 nanotubes)563.5 mu mol.h(-1) g(-1)) and BiVO4-TiO2 (915.7 mu mol.h(-1) g(-1)), respectively. The excellent enhancing effect of rGO on photocatalytic performance of the heterojunction formed between these materials was attributed to the large surface area, light absorption capacity due to band gap engineering, and separation of photo-generated charge carriers. It demonstrates the design of the ternary BiVO4-TiO2/rGO hetero-nanostructures that was proposed in the present strategy could effectively separate the electron-hole pairs for sustainable photocatalytic H-2 production, as was verified by PL, TRF and EIS photospectroscopy measurements. (C) 2020 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.