Interfacial optimization of Z-scheme Ag3PO4/MoS2 nanoflower sphere heterojunction toward synergistic enhancement of visible-light-driven photocatalytic oxygen evolution and degradation of organic pollutant

Samples of flower-like MoS2 nanosphere-modified Ag3PO4 (Ag3PO4/MoS2) were prepared by a facile and reliable method. The morphology and crystal structure of the Ag3PO4/MoS2 composites were investigated by high-resolution transmission electron microscopy, X-ray diffraction, specific surface areas, and X-ray photoelectron spectroscopy. Analysis results indicated that Ag3PO4 particles were distributed conformably on the surface of flower-like MoS2 spheres, and both formed an enhanced heterojunction structure. Fluorescence spectra, surface photocurrent spectra, and electrochemical impedance spectroscopic results showed that an appropriate amount of MoS2 modification (6 mg) could effectively improve the generation, separation, and migration efficiency of the photogenerated electron/hole pairs (e(-)/h(+)). The photocatalytic activity of the samples was evaluated by photocatalytic O-2 production and photodegradation of the organic molecules under visible-light irradiation. With the increase in the amount of MoS2, the photocatalytic activity of the Ag3PO4/MoS2 samples increased first and then decreased. The photocatalytic rate reached the fastest when the mass of MoS2 was 6 mg, which was 7.66- and 9.28-fold of that of pure Ag3PO4 for pho-tocatalytic O-2 production and photodegradation of organic molecules, respectively. Sacrificial reagent ex-periments and electron spin resonance spectra showed that superoxide radicals (center dot O-2(-)) and holes (h(+)) played a major role in the photocatalytic reaction process. The enhanced photocatalytic performance could be ascribed to the interfacial optimization and formation of Z-scheme heterojunction. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Samples of flower-like MoS2 nanosphere-modified Ag3PO4 were prepared by a facile and reliable method, showing enhanced photocatalytic performance. The analysis results indicated the improved generation, separation, and migration efficiency of photogenerated electron/hole pairs with an appropriate amount of MoS2 modification. The photocatalytic activity of the samples increased first and then decreased as the amount of MoS2 increased, reaching the fastest rate at 6 mg.