Fabrication of core-shell BiVO4@Fe2O3 heterojunctions for realizing photocatalytic hydrogen evolution via conduction band elevation

Abstract

Core-shell heterostructured BiVO4@Fe2O3 photocatalysts are fabricated through a facile solution combustion and in-situ precipitation methods. Transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) images verify their core-shell structure. X-ray photoelectron spectroscopy (XPS) results indicate there are interaction between BiVO4 and Fe2O3, confirming the formation of heterojunction. Mott–Schottky measurements exhibit that hybridizing with Fe2O3 makes the conduction band of BiVO4 to be shifted up by 1.05 V from 0.21 to −0.84 V, which endows BiVO4 to be effective for photocatalytic H2 generation. Meanwhile, photoluminescence spectra show that the heterosturcture decreases the recombination efficiency of photo-induced electrons and holes. Hydrogen experiments indicate that BiVO4@Fe2O3 composite containing 10 wt% Fe2O3 has the highest catalytic activity. Keywords: BiVO4/Fe2O3 heterojunction, Solution combustion synthesis, Hydrogen production, Core-shell structure, Visible-light photocatalysis