Ammonium phosphotungstate nanoparticle/ultrathin g-C3N4 composite photocatalysts with Z-scheme heterojunctions: preparation and application to organic contaminant degradation

Abstract

Abstract Owing to their advantageous physical, chemical, electronic, and optical properties, two-dimensional (2D) materials are widely used as highly active visible-light photocatalysts. In this study, 3D/2D composite photocatalysts were prepared from ammonium phosphotungstate nanoparticles and 2D ultrathin graphitic carbon nitride by an impregnation method and were found to efficiently promote the photodegradation of rhodamine B and tetracycline in water under visible light irradiation. Photocatalytic degradation was maximum at a PW12NH4 loading of 20 wt% (UCN20), with photodegradation efficiencies of 93.40% and 69.6% for RhB and TC, respectively. The photocatalytic degradation rate using UCN20 was 5.8-fold higher for RhB and 2.2-fold higher for TC compared to those with UCN. This high performance is ascribed to the large specific surface areas and pore volumes of the composites and the reduced probability of photogenerated carrier recombination therein. The related degradation mechanism is believed to involve a Z-scheme charge transfer mode, which enhances the redox capability of composite photocatalysts and renders them suitable for the visible light-driven remediation of wastewater containing organic contaminants.