Enhanced photocatalytic overall water splitting via MOF-derived tetragonal BiVO4-based solid solution

Abstract

In this work, BiVO4-based solid solutions, Bi0.5Y0.5VO4, were prepared via the MOF-derived method initially. The physical and chemical properties of the Bi0.5Y0.5VO4 samples were characterized by XRD, Raman spectra, XPS, HRTEM, element mapping, UV–vis DRS spectrum, TRPL and electrochemical analysis. The results showed that Y sources will be beneficial for the generation of tetragonal phase BiVO4, which made Bi0.5Y0.5VO4 samples constructed by tetragonal Bi0.5Y0.5VO4 and amorphous Bi0.5Y0.5VO4. The ratio of the tetragonal Bi0.5Y0.5VO4 was changed if the variation of the calcined time increased, which could be ascribed to the conversion of the amorphous Bi0.5Y0.5VO4. Consequently, photocatalytic overall water splitting property was enhanced and the results exhibited that Bi0.5Y0.5VO4-10 h samples exhibited the best performance with a rate of 124.2 μmol H2 and 61.7 μmol O2 per hour. The reason could be attributed to the variation of twisting degree, which thus influencing the internal electric field of the materials. More importantly, after metallic Pt particles as co-catalysts deposited, the ratio of H2:O2 was decreased. It could be proposed that the electric field shield effect will emerge to regulate the interfacial internal electric field further, which could play an essential role in the procedure of photocatalytic water splitting, especially for the reduction procedure.