Photocatalytic activity of Pt-modified Bi2WO6 nanoporous wall under sunlight

In this work, Bi2WO6 nanoporous wall was synthesized by using Bi2O3 as template and Bi source. Pt nanoparticles whose average size is about 8 nm were further immobilized on the Bi2WO6 nanoporous wall via a simple chemical reduction process. Their photocatalytic activity and the effect of Pt modification were studied by analyzing the degradation of an organic dye, rhodamine 6G (Rh6G), under simulated sunlight. It was found that the photocatalytic ability of Bi2WO6 nanoporous wall was enhanced by introducing Pt nanoparticles. Bare Bi2WO6 shows a degradation efficiency of 78 % after 1 h, while the degradation efficiency of 5 wt% Pt-modified Bi2WO6 was 99 %, and on further increasing the Pt content in the as-prepared Pt-modified Bi2WO6 catalysts, their photocatalytic ability will decrease. The optimal catalyst could be reused without any decrease for five cycles, which may due to Pt be able to help trap the conduction band electrons in the absence of Rh6G. A possible photocatalytic mechanism was proposed and further proved by transient photocurrent response experiment.