Facile preparation of KBiO3/g‐C3N4 composites with microwave irradiation for photocatalytic hydrogen production

BACKGROUND KBiO3/g‐C3N4 composites were prepared under microwave irradiation to different weight ratios of KBiO3 (5, 10, 20, 30, 40, 50, 60, 70 80, 90%wt) using a Mars‐6 microwave for 30 min at 100 W. The samples were characterized by X‐ray diffraction (XRD), Fourier transform infrared (FT‐IR) spectroscopy, scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS)‐ mapping, N2 physisorption and diffuse reflection spectroscopy (DRS). The photocatalytic activity of the samples was evaluated in the hydrogen evolution reaction. RESULTS The composites were confirmed by XRD, where it was observed that in samples with up to 60% KBiO3 it is easy to identify the characteristic peak of g‐C3N4. Composites show that KBiO3 was homogeneously dispersed on g‐C3N4 according to EDS‐mapping observations. In the photocatalytic tests it was observed that when the concentration of g‐C3N4 was greater than that of KBiO3, but up to a certain limit, there was greater production of hydrogen. CONCLUSIONS KBiO3/g‐C3N4 composites were prepared successfully with microwave irradiation, reaching a good synergy between both materials for hydrogen production reaction. This synergy was improved by the use of microwaves that facilitate the dispersion and binding of both materials. The sample with best hydrogen production was 40%KBiO3/60%C3N4 with 698 µmol H2 g−1, which is about three times higher than that of g‐C3N4 and seven times higher than that of KBiO3. © 2019 Society of Chemical Industry