No abstract

Solar CO reduction efficiency is largely limited by poor photoabsorption, sluggish electron-hole separation, and a high CO activation barrier. Defect engineering was employed to optimize these crucial processes. As a prototype, BiOBr atomic layers were fabricated and abundant oxygen vacancies were deliberately created on their surfaces. X-ray absorption near-edge structure and electron paramagnetic resonance spectra confirm the formation of oxygen vacancies. Theoretical calculations reveal the creation of new defect levels resulting from the oxygen vacancies, which extends the photoresponse into the visible-light region. The charge delocalization around the oxygen vacancies contributes to CO conversion into COOH* intermediate, which was confirmed by in situ Fourier-transform infrared spectroscopy. Surface photovoltage spectra and time-resolved fluorescence emission decay spectra indicate that the introduced oxygen vacancies promote the separation of carriers. As a result, the oxygen-deficient BiOBr atomic layers achieve visible-light-driven CO reduction with a CO formation rate of 87.4 μmol g h , which was not only 20 and 24 times higher than that of BiOBr atomic layers and bulk BiOBr, respectively, but also outperformed most previously reported single photocatalysts under comparable conditions.

Bismuth tungstate hierarchical nest-like structures built by higher order nanoplate alignment have been successfully synthesized by a facile and economical method in the presence of polyvinyl pyrrolidone. The formation mechanism and effect of reaction time on the products were investigated. In addition, studies of the photocatalytic property demonstrate that the as-synthesized Bi2WO6 structures show excellent photocatalytic activity exposure to visible light irradiation. Furthermore, we first explored the electrochemical property of the Bi2WO6 nanostructure as an electrode in a lithium ion battery. Therefore, the preparation and properties studies of Bi2WO6 structures suggest potential future applications in photocatalysis by sunlight and as an electrode candidate in lithium ion batteries.