In Situ Synthesis of V⁴⁺ and Ce³⁺ Self-Doped BiVO₄/CeO₂ Heterostructured Nanocomposites with High Surface Areas and Enhanced Visible-Light Photocatalytic Activity

In order to achieve high performance in visible-light photocatalysis, V 4+ and Ce 3+ self-doped BiVO 4 /CeO 2 heterostructured nanocomposites with high surface areas were prepared using the templating approach employing mesoporous silica MCM-41 as the hard template. X-ray photoelectron spectroscopy (XPS) spectra have demonstrated the presence of plentiful V 4+ and Ce 3+ species in the nanocomposites accompanied by the formation of oxygen vacancies. The presence of V 4+ species is further identified by the electron spin resonance (ESR) spectrum. Furthermore, the BiVO 4 and CeO 2 could be affecting each other by arousing the structural changes in the formed nanocomposites. The V 4+ and Ce 3+ self-doped 0.4BiVO 4 /0.6CeO 2 nanocomposite with the surface area as large as 78.35 m 2 /g exhibits the highest photocatalytic activity for the rhodamine B (RhB) and methyl orange (MO) degradation and photoelectrochemical performances. The enhanced photocatalytic mechanism is systematically studied via UV–vis diffuse reflectance spectra (DRS), photoluminescence (PL) spectra, transient photocurrent responses, and electrochemical impedance spectroscopy (EIS) spectra. The remarkable enhanced photocatalytic activity could be mainly attributed to the formed heterojunction nanostructures, the presence of defect states induced by oxygen vacancies, and self-doped V 4+ and Ce 3+ centers, as well as high surface areas. A possible photocatalytic mechanism over the V 4+ and Ce 3+ self-doped BiVO 4 /CeO 2 nanocomposites is proposed based on the active species trapping experiments and calculated energy band structures.