BiVO3/g-C3N4 S-scheme heterojunction nanocomposite photocatalyst for hydrogen production and amaranth dye removal

Nanoparticles of BiVO3/g-C3N4 heterojunctions embedded two semiconductor of matching band gap energy was employed for photodegradation of amaranth dye and evolution of huge amount of hydrogen gas. A simple thermal decomposition of urea is efficient route for producing g-C3N4 nanosheets. In ultrasonic bath of power intensity 150 Watt, BiVO3 nanoparticles were deposited homogeneously on g-C3N4 surface. The localization of BiVO3 nanoparticles on the corners of g-C3N4 sheets was proved with HRTEM analysis. With increasing BiVO3 contents to 10 wt%, the photocatalytic hydrogen evolution rate reach a maximum value of 6.8 mmolg(-1)h(-1) which is ten fold higher than that of bare g-C3N4. The sonicated nanocomposites were characterized by XRD, N-2-adsorption-desorption isotherm, HRTEM, XPS, DRS and PL. The influence of radiation power of ultrasound waves on the dye degradation and the amount of hydrogen evolved was established. The production of charge carriers with high reductive and oxidative power through step S-scheme mechanism is primary cause for the exceptional photocatalytic efficiency of the nanocomposites. The charge migration through step S-scheme mechanism rather than type (II) heterojunction mechanism was established by the PL measurements of terephthalic acid and the trapping scavengers experiments. Nanocomposite with 10 wt% BiVO3 possesses a superior reactivity for six consecutive cycles reveal the high stability of the as-synthesized sample.