2D BiVO4/g-C3N4 Z-scheme photocatalyst for enhanced overall water splitting

Abstract

A 2D Z-scheme BiVO4/g-C3N4 photocatalyst was successfully synthesized by a two-step hydrothermal/calcination method for overall water splitting. Morphology design to restrain the growth of BiVO4 nanoplates with thickness around 20 nm was achieved by adjusting the pH value and introducing graphene sheets. Then, the BiVO4/g-C3N4 (BVO-CN) hybrid photocatalysts were fabricated with different mass ratios of two components. The structures and optical properties of the BVO-CN photocatalysts were characterized by transmission electron microscope, scanning electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, and photoluminescence spectroscopy. In application, the BVO-CN photocatalysts exhibited the catalytic overall water splitting activity up to 15.6 μmol h−1 for H2 production and 7.3 μmol h−1 for O2 evolution under visible light irradiation. A possible Z-scheme mechanism is proposed for the enhanced photocatalytic activity and was further confirmed by electron spin resonance spectroscopy. This study demonstrated enhanced overall water splitting photocatalytic performance of BiVO4/g-C3N4 photocatalyst by constructing a 2D nanoplates morphology and shed light on the morphology design of Z-scheme semiconductor materials.