Vásquez G Cristian, Maestre David, Cremades Ana, Ramírez-Castellanos Julio, Magnano Elena, Nappini Silvia, Karazhanov Smagul Zh
Departamento de Física de Materiales, Facultad de CC. Físicas, Universidad Complutense, 28040, Madrid, Spain.
Department for Solar Energy, Institute for Energy Technology, 2007, Kjeller, Norway.
Sci Rep. 2018 Jun 7;8(1):8740. doi: 10.1038/s41598-018-26728-3.
The effects of Cr on local environment and electronic structure of rutile TiO are studied combining theoretical and experimental approaches. Neutral and negatively charged substitutional Cr impurities Cr and Cr as well as Cr-oxygen vacancy complex 2Cr + V are studied by the density functional theory (DFT) within the generalized gradient approximation (GGA) of Perdew-Burke-Ernzerhof (PBE) functional. Experimental results based on X-Ray absorption spectroscopy (XAS) and X-Ray photoelectron spectroscopy (XPS) performed on Cr doped TiO at the Synchrotron facility were compared to the theoretical results. It is shown that the electrons of the oxygen vacancy tend to be localized at the t states of the Cr ions in order to reach the stable oxidation state of Cr. Effects of Cr on crystal field (CF) and structural distortions in the rutile TiO cell were analyzed by the DFT calculations and XAS spectra revealing that the CF and tetragonal distortions in TiO are very sensitive to the concentration of Cr.
结合理论和实验方法研究了Cr对金红石型TiO局部环境和电子结构的影响。采用Perdew-Burke-Ernzerhof（PBE）泛函的广义梯度近似（GGA）下的密度泛函理论（DFT）研究了中性和带负电荷的替代Cr杂质Cr和Cr以及Cr-氧空位复合体2Cr + V。将在同步加速器装置上对Cr掺杂TiO进行的基于X射线吸收光谱（XAS）和X射线光电子能谱（XPS）的实验结果与理论结果进行了比较。结果表明，氧空位的电子倾向于定域在Cr离子的t态，以达到Cr的稳定氧化态。通过DFT计算和XAS光谱分析了Cr对金红石型TiO晶胞中晶体场（CF）和结构畸变的影响，结果表明TiO中的CF和四方畸变对Cr的浓度非常敏感。
