Strain-Induced Photocatalytic H 2 Production over BiVO 4 in Pure Water without Any Cocatalyst.

In this study, BiVO 4 nanosheets (BiVO 4 -NS) were prepared by a facile hydrothermal method. It is found that sonication-induced strain can effectively promote the H 2 production over BiVO 4 -NS in the presence of pure water without any cocatalysts. With the assistance of the sonication, the H 2 production over BiVO 4 -NS is 1.344 mmol·g -1 after 3 h simulated sunlight irradiation, which is 24.8 times higher than that of BiVO 4 -NS without sonication (0.054 mmol·g -1 ). In addition, the products of water oxidation are determined to be hydroxyl radicals and hydrogen peroxide. Moreover, BiVO 4 -NS also shows obviously enhanced photoactivity than that of the commercially available BiVO 4 nanoparticles (BiVO 4 -C). The improved photoactivity of BiVO 4 -NS is attributed to the effective charge separation and low charge transfer resistance. The underlying mechanism of sonication-promoted water splitting is investigated by a variety of controlled experiments. The results show that ultrasonic waves can produce obvious strain inside the sample, which results in lattice distortion of BiVO 4 . Therefore, the conduction band of BiVO 4 is obviously negative shifted, which is beneficial for H 2 production. In addition, the strain in BiVO 4 also produces local polarization of the sample, which effectively promotes the charge transfer and separation process. It is hoped that our study could provide a new strategy for achieving efficient photocatalytic water splitting.