Akiyama Kensuke, Nojima Sakiko, Ito Yuko, Ushiyama Mikio, Okuda Tetsuya, Irie Hiroshi
Kanagawa Institute of Industrial Science and Technology, 705-1 Shimoizumi, Ebina, Kanagawa 243-0435, Japan.
Clean Energy Research Center, University of Yamanashi, 4-3-11 Takeda, Kofu, Yamanashi 400-8511, Japan.
ACS Omega. 2022 Oct 17;7(43):38744-38751. doi: 10.1021/acsomega.2c04360. eCollection 2022 Nov 1.
A solid-state Z-scheme system is constructed whereby rutile titania (TiO) and beta-iron disilicide (β-FeSi) were combined to act as oxygen (O)- and hydrogen (H)-evolution photocatalysts, respectively, connected by gold (Au). β-FeSi island grains with diameters in the 0.5-2 μm range were formed on the surface of Au-coated TiO powder by the co-sputtering method. On the surface of TiO powder, the Au-Si liquidus phase was obtained via a Au-Si eutectic reaction, which contributed to the selective deposition and crystallization of β-FeSi island grains onto Au. After the loading of the H-evolution cocatalysts platinum and chromium oxide onto β-FeSi, the system obtained catalyzed the evolution of H and O in a stoichiometric ratio from pure water under ultraviolet light irradiation. The transfer of photoexcited electrons in the conduction band (CB) of β-FeSi to Pt causes the reduction of protons to H, and the photogeneration of holes in the valence band (VB) of TiO causes the oxidation of water to O. In addition, the photogenerated holes in the VB of β-FeSi and the photoexcited electrons in the CB of TiO combined with each other in the Au layer, affording the completion of the overall photocatalytic water-splitting.
构建了一种固态Z型体系，其中金红石型二氧化钛（TiO₂）和β-二硅化铁（β-FeSi₂）分别作为析氧（O）和析氢（H）光催化剂，通过金（Au）连接。通过共溅射法在涂覆有Au的TiO₂粉末表面形成了直径在0.5 - 2μm范围内的β-FeSi₂岛状晶粒。在TiO₂粉末表面，通过Au - Si共晶反应获得了Au - Si液相，这有助于β-FeSi₂岛状晶粒在Au上的选择性沉积和结晶。在将析氢助催化剂铂和氧化铬负载到β-FeSi₂上之后，该体系在紫外光照射下能以化学计量比催化从纯水中析氢和析氧。β-FeSi₂导带（CB）中的光激发电子转移到Pt导致质子还原为H₂，TiO₂价带（VB）中的光生空穴导致水氧化为O₂。此外，β-FeSi₂价带中的光生空穴与TiO₂导带中的光激发电子在Au层中相互结合，从而完成了整个光催化水分解过程。
