Abstract
In the current study, a mediator-free solid-state BiVO(4)/pyridine-doped g-C(3)N(4) nano-Z-scheme photocatalytic system (BDCN) with superior visible-light absorption and optimized photocatalytic activity was constructed via an in situ hydrothermal method for the first time. The pyridine-doped g-C(3)N(4) (DCN) nanosheets show strong absorbance in the visible-light region by pyridine doping, and the BiVO(4) (∼10 nm) nanoparticles are successfully in situ grown on the surface of DCN nanosheets by the controlled hydrothermal method. Under the irradiation of visible light (λ > 420 nm), the BiVO(4)/DCN nanocomposite photocatalysts efficiently degrade phenol and methyl orange (MO) and display much higher photocatalytic activity than the individual DCN, bulk BiVO(4), or the simple physical mixture of DCN and BiVO(4). The greatly improved photocatalytic ability is attributed to the construction of the direct Z-scheme system in the BiVO(4)/DCN nanocomposite free from any mediator, which leads to enhanced separation of photogenerated electron-hole pairs, as confirmed by the photocurrent analysis. The possible Z-scheme mechanism of the BiVO(4)/DCN nanocomposite photocatalyst was investigated by transient time-resolved luminescence decay spectrum, active species trapping experiments, electron paramagnetic resonance (EPR) technology, and hydrogen evolution test.