Graphene oxide mediated co-generation of C-doping and oxygen defects in Bi2WO6 nanosheets: a combined DRIFTS and DFT investigation

In order to efficiently control air pollutants using photocatalytic technology, the co-generation of C-doping and oxygen vacancies (OVs) in Bi2WO6 (BWO) nanosheets was achieved by a graphene oxide (GO)-mediated hydrothermal method. The photocatalytic performance was highly improved with the synergistic effects of C-doping and OVs. The experimental characterization and DFT calculations were closely combined to reveal that the C element could serve as both an electron acceptor and channel for charge transfer to promote charge separation. Meanwhile, the OVs could induce the formation of a defect level in the band gap which increases the production of OH as the primary reactive species by introducing more light-generated holes into the valence band. Meanwhile, the OVs could enhance the generation of O-2(-) species via the promotion of O-2 adsorption and activation on the catalyst surface. Moreover, the reaction intermediates were monitored and the mechanism of photocatalytic NO oxidation was proposed based on in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The design concept of photocatalyst modification with C-doping and OVs could offer a novel strategy to enhance the performance for environmental applications.