Growth of BiVO4 Nanoparticles on a Bi2O3 Surface: Effect of Heterojunction Formation on Visible Irradiation-Driven Catalytic Performance

• Published in: Journal of physical chemistry. C 2017-06, Vol.121 (25), p.13747-13756
• Main Authors: Lopes, Osmando F, Carvalho, Kele T. G, Avansi, Waldir, Ribeiro, Caue
• Format: Article
• Language: English
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/acs.jpcc.7b03340

Heterostructured materials composed of different semiconductors can be used to decrease rapid charge carrier recombination in photocatalysts, but the development of efficient synthesis methods for these materials remains a challenge. This work describes a novel strategy for tailoring heterostructures that is based on the solubility difference between two semiconductors with at least one metal in common. The growth of BiVO4 on a preformed Bi2O3 particle was used as a model for heterojunction formation. The number of Bi2O3/​BiVO4 heterojunctions was tuned using synthesis variables (temperature and V concentration) and the particle size of the preformed Bi2O3. The synthesis of the Bi2O3/​BiVO4 heterostructures using Bi2O3 nanoparticles resulted in a larger quantity of heterojunctions due to the higher solubility of the nanoparticles compared to micrometric Bi2O3, which led to a classical heterogeneous precipitation on the preformed surfaces. The proposed growth mechanism was effective for obtaining heterostructured Bi2O3/​BiVO4 semiconductors with enhanced photocatalytic performances compared to the isolated phases. The greater photoactivity of the heterostructures could be explained by the increased spatial separation in the photogenerated electron/hole pairs due to the formation of a type-II heterostructure and was observed by time-resolved photoluminescence analysis. In this case, the photogenerated electrons were transferred from the conduction band of the p-type semiconductor (Bi2O3) to the n-type (BiVO4) semiconductor, while the photogenerated holes were transferred from the valence band of the n-type semiconductor to the p-type semiconductor.