Fabrication of Z-scheme TiO₂/BP/g-C₃N₄ nanocomposite via pulsed laser ablation in liquid for photocatalytic overall water splitting

Indirect Z-scheme heterostructure photocatalysts possess great potential for simulated light-induced overall water splitting. However, the fabrication of highly-efficient indirect Z-scheme heterostructures under solar light irradiation remains a great challenge. In this work, a novel ternary nanocomposite material comprising of TiO₂ nanowires, g-C₃N₄ nanosheets, and black phosphorous (BP) has been fabricated successfully using pulsed laser ablation technique. A series of characterization techniques were exploited to elucidate the optical, structural, and morphological attributes of the synthesized nanostructure. Under simulated light irradiation, the fabricated TiO₂/BP/g-C₃N₄ nanocomposite displayed stable and efficient photocatalytic overall water splitting performance with hydrogen and oxygen evolution rate of 118.2 and 240 μmol g⁻¹h⁻¹, respectively. The nanocomposite showed an Apparent Quantum Yield (AQY) of 7.8% (400 nm), excellent photocatalytic activity i.e. (≈5.4 times higher than TiO₂/BP nanocomposite), and stability. The significant enhancement in the photocatalytic efficiency of the fabricated nanocomposite is attributed to the collective gains arising from the low bandgap, large surface area, and formation of Z-scheme that facilitated charge separation on the TiO₂/BP/g-C₃N₄ nanocomposite.