AuOx Surface Oxide Layer as a Hole-Transferring Cocatalyst for Water Oxidation over Au Nanoparticle-Decorated TiO2 Photocatalysts
AuOx Surface Oxide Layer as a Hole-Transferring Cocatalyst for Water Oxidation over Au Nanoparticle-Decorated TiO2 Photocatalysts
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DOI：
10.1021/acsanm.2c01186
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发表时间：
2022-07
影响因子：
5.9
通讯作者：
Eri Fudo;A. Tanaka;H. Kominami
中科院分区：
文献类型：
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作者：
Eri Fudo;A. Tanaka;H. Kominami
由于水的氧化是水分解的速率决定步骤，因此开发对水的四电子氧化具有高活性的光催化剂是重要的。采用沉积沉淀法（DP）制备了金（Au）纳米粒子修饰的二氧化钛（TiO 2）（Au/TiO 2），并在不同温度下分别通入氧气（O2）或氢气（H2）进行热处理。采用紫外-可见光谱、透射电子显微镜（TEM）和X射线光电子能谱（XPS）对样品进行了表征。当Au/TiO 2样品在H2中处理时，所有的Au纳米颗粒都处于金属状态。当Au/TiO 2样品在氧气中处理时，Au纳米颗粒外表面的Au原子被部分氧化，导致Au/TiO 2中形成Au核-AuOx壳结构。在可见光照射下，具有Au核-AuOx壳结构的Au/TiO 2等离子体光催化剂比金属Au/TiO 2样品具有更高的活性。氧化和还原产物沉积在Au/TiO 2光催化剂上的模型反应表明，还原和氧化位点分别位于TiO 2表面和AuOx层。在此基础上讨论了AuOx层的作用以及Au/TiO 2等离子体光催化剂对水的氧化反应机理。
The development of a photocatalyst having high activity for four-electron oxidation of water is important because water oxidation is the rate-determining step of water splitting. Titanium(IV) oxide (TiO2) modified with gold (Au) nanoparticles (Au/TiO2) was prepared by the deposition precipitation (DP) method and then thermally treated under a flow of oxygen (O2) or hydrogen (H2) at various temperatures. These Au/TiO2samples were characterized by UV–vis spectroscopy, transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). When the Au/TiO2sample was treated in H2, all of the Au nanoparticles were in a metallic state. When the Au/TiO2sample was treated in O2, Au atoms at the outer surface of Au nanoparticles were partially oxidized, resulting in the formation of an Au core–AuOxshell-like structure in Au/TiO2. In water oxidation under visible-light irradiation, Au/TiO2plasmonic photocatalysts having the Au core–AuOxshell-like structure were more active than metallic Au/TiO2samples. Model reactions in which oxidation and reduction products were deposited on the Au/TiO2photocatalyst indicated that the reduction and oxidation sites were the TiO2surface and the AuOxlayer, respectively. The role of an AuOxlayer and the reaction mechanism of water oxidation over Au/TiO2plasmonic photocatalyst are discussed on the basis of the results.