The charge transfer mechanism of Bi modified TiO2 nanotube arrays: TiO2 serving as a “charge-transfer-bridge”
Abstract The surface of Bi nanoparticles would be oxidized to amorphous Bi 2 O 3 layer with thickness about 7nm in the air. Until now, it is still unclear about the different roles of Bi and Bi 2 O 3 in the photocatalysis when Bi nanoparticles are deposited on semiconductors. In this work, Bi nanospheres have been decorated on the top aperture of TiO 2 nanotube arrays by vapor deposition method, and an X-ray photoelectron spectroscopy combined with synchronous illumination technique is applied to explore the charge transfer mechanism. Under visible light, the electrons generated from the surface plasmon resonance of Bi would transfer to the conduction band of TiO 2 first, and then migrate to the oxide surface of Bi 2 O 3 and reduce it to metallic Bi. During this process, TiO 2 serves as a “charge-transfer-bridge” and the reductive reaction would not occur in the absence of it. And the energy of the immigrant electrons differs from the self-excited ones, which can not trigger the reductive reaction. These findings have resolved the puzzles about the utilization of Bi, and figured out the different roles of Bi and Bi 2 O 3 in the photocatalytic process. Furthermore, the photoelectrochemical activities of Bi modified TiO 2 nanotubes arrays have been systematically explored and it is found that the photocurrent of TiO 2 nanotube arrays could be significantly improved due to the surface plasmon resonance of Bi as well as the optimized charge transfer and transport characteristics. Highlights The different roles of Bi and Bi 2 O 3 in photocatalytic process are firstly investigated. The charge transfer pathway of Bi loaded TiO 2 is clearly studied by in situ XPS method. It is proved that the improvement of TiO 2 PEC performances originate from the SPR of Bi. It is proposed that the energy of immigrant electrons and self-excited ones are different. Graphical abstract [DISPLAY OMISSION]
유료 다운로드의 경우 해당 사이트의 정책에 따라 신규 회원가입, 로그인, 유료 구매 등이 필요할 수 있습니다. 해당 사이트에서 발생하는 귀하의 모든 정보활동은 NDSL의 서비스 정책과 무관합니다.
원문복사신청을 하시면, 일부 해외 인쇄학술지의 경우 외국학술지지원센터(FRIC)에서
무료 원문복사 서비스를 제공합니다.
NDSL에서는 해당 원문을 복사서비스하고 있습니다. 위의 원문복사신청 또는 장바구니 담기를 통하여 원문복사서비스 이용이 가능합니다.
- 이 논문과 함께 출판된 논문 + 더보기