Alotabi Abdulrahman S, Small Thomas D, Yin Yanting, Osborn D J, Ozaki Shuhei, Kataoka Yuki, Negishi Yuichi, Domen Kazunari, Metha Gregory F, Andersson Gunther G
Flinders Institute for Nanoscale Science and Technology, Flinders University, Adelaide, South Australia 5042, Australia.
Department of Physics, Faculty of Science and Arts in Baljurashi, Albaha University, Baljurashi 65655, Saudi Arabia.
ACS Appl Mater Interfaces. 2023 Mar 12. doi: 10.1021/acsami.3c00250.
Chromium oxide (CrO) is a beneficial metal oxide used to prevent the backward reaction in photocatalytic water splitting. The present work investigates the stability, oxidation state, and the bulk and surface electronic structure of Cr-oxide photodeposited onto P25, BaLaTiO, and Al:SrTiO particles as a function of the annealing process. The oxidation state of the Cr-oxide layer as deposited is found to be CrO on the surface of P25 and Al:SrTiO particles and Cr(OH) on BaLaTiO. After annealing at 600 °C, for P25 (a mixture of rutile and anatase TiO), the CrO layer diffuses into the anatase phase but remains at the surface of the rutile phase. For BaLaTiO, Cr(OH) converts to CrO upon annealing and diffuses slightly into the particles. However, for Al:SrTiO, the CrO remains stable at the surface of the particles. The diffusion here is due to the strong metal-support interaction effect. In addition, some of the CrO on the P25, BaLaTiO, and Al:SrTiO particles is reduced to metallic Cr after annealing. The effect of CrO formation and diffusion into the bulk on the surface and bulk band gaps is investigated with electronic spectroscopy, electron diffraction, DRS, and high-resolution imaging. The implications of the stability and diffusion of CrO for photocatalytic water splitting are discussed.
氧化铬（CrO）是一种有益的金属氧化物，用于防止光催化水分解中的逆反应。本工作研究了光沉积在P25、BaLaTiO和Al:SrTiO颗粒上的Cr氧化物的稳定性、氧化态以及体相和表面电子结构随退火过程的变化。发现沉积态的Cr氧化物层在P25和Al:SrTiO颗粒表面为CrO，在BaLaTiO上为Cr(OH)。在600°C退火后，对于P25（金红石和锐钛矿TiO的混合物），CrO层扩散到锐钛矿相中，但保留在金红石相表面。对于BaLaTiO，Cr(OH)在退火时转变为CrO并略微扩散到颗粒中。然而，对于Al:SrTiO，CrO在颗粒表面保持稳定。这里的扩散归因于强金属-载体相互作用效应。此外，P25、BaLaTiO和Al:SrTiO颗粒上的一些CrO在退火后还原为金属Cr。利用电子能谱、电子衍射、DRS和高分辨率成像研究了CrO形成及其向体相扩散对表面和体相带隙的影响。讨论了CrO的稳定性和扩散对光催化水分解的影响。
