Nano-zero-valent iron and MnOx selective deposition on BiVO4 decahedron superstructures for promoted spatial charge separation and exceptional catalytic activity in visible-light-driven photocatalysis-Fenton coupling system

Novel nano-zero-valent iron (Fe-0)/MnOx/BiVO4 ternary magnetic assemblies are fabricated through hydro thermal and photo-deposition strategy. The assemblies are characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, photoluminescence, X-ray photoelectron spectroscopy, and UV-vis diffuse reflectance spectroscopy. Fe as a reduction cocatalyst are deposited on surface of monoclinic BiVO4 decahedron supersturcture. Meanwhile, MnOx as an oxidation cocatalyst is selectively anchored on oxidative {110} facet of BiVO4 by photodeposition. The photogenerated electrons and holes can be transmitted to Fe-0 and MnOx, respectively, which favors the spatial charge separation. The adjunction of Fe-0 significantly enhances light absorption, and forms a photocatalysis-Fenton coupling system simultaneously. The assemblies with narrow band gap of 2.10 eV display an exceptional photocatalytic activity, and the visible-light-driven photocatalytic degradation ratio of 2,4-dichlorophenol and Bisphenol A are up to 95.4 and 91.4%, respectively, which are several times higher than that of pristine BiVO4. This is ascribed to the selective decoration of Fe-0 and MnOx favoring the spatial charge separation, and the photocatalysis-Fenton coupling system enhancing degradation. Moreover, the superior magnetic property due to Fe-0 decoration realizes magnetic separation of catalysts, which is favorable in practical applications.