WO3/BP/g-C3N4 –based cauliflower nanocomposite fabricated by pulsed laser ablation for overall water splitting

Abstract

Fast recombination of photoinduced charge carriers due to poor charge separation are the fundamental challenges of particulate photocatalysis. One of the key solutions to mitigate these problems is the construction of heterojunction nanocomposites. In this study, we present a heterojunction composing of tungsten oxide/ black phosphorous and graphitic nitride (WO3/BP/g-C3N4) fabricated via pulsed laser ablation in liquid. To highlights the synergistic role of the fabricated components, the following photocatalysts were also prepared, WO3, WO3/BP, and g-C3N4. The overall photocatalytic production of hydrogen was examined for WO3, WO3/BP, g-C3N4, and WO3/BP/g-C3N4. There was no detectable production of hydrogen gas for the WO3 and g-C3N4. However, the hydrogen production rate was approximately 75 µmolg−1h−1 for the WO3/BP. The production rate substantially increased to 400 µmolg−1h−1 for the WO3/BP/g-C3N4 photocatalyst. The enhancement can be attributed to the cumulative increase in the UV–visible light absorption, mainly by BP and partially g-C3N4 in the fabricated WO3/BP/g-C3N4, as well as the effective charge transport leading to separation of charge carriers which is well explained using the Z-scheme mechanism. Moreover, the WO3/BP/g-C3N4 composite catalysts produced stable and consistent results after a prolonged operation which indicates the reusability of the photocatalyst.