铂团簇负载锐钛矿二氧化钛纳米管电子结构及光学性质

Electronic Structure and Optical Property of Platinum Clusters Adsorption on the Anatase Titanium Dioxide Nanotube

基于密度泛函理论的广义梯度近似对Ptn(n=1～3)团簇负载锐钛矿二氧化钛纳米管的电子结构、吸附能及光学性质进行第一性原理计算。将锐钛矿TiO2垂直于[101]向剪切得到(101)面,经卷曲而成TiO2纳米管理论模型。在最优化结构的基础上负载Pt团簇,分别考察Pt1、Pt2、Pt3的可能稳定构型,通过比较吸附能,得出各自的最稳定构型。结果表明,Ptn团簇优先负载于O2f-O2f桥氧位,说明这可能是一个成核中心。电子态密度及吸收光谱分析表明,引入Ptn团簇使光学带隙变窄,吸收边带红移。

The electronic structure, adsorption and optical properties of Pt, （n = 1-3） clusters loaded anatase TiO2 nanotube were investigated based on the density functional theory with generalized gradiemt approximation. The TiO2 nanotube was obtained by rolling up TiO2 （101） surface, which was prepared by shearing anatase bulk TiO2 perpendicular to [10T] direction. The possible configu- rations of adsorbed Pt monomers, dimmers and trimers at optimized TiO2 nanotube were investigated, respectively. The most stable structure was found via the comparison of the adsorption energies. The results show that Pt adatoms can favor the bridging oxygen O2f-O2f site along [010], indicating that the bridging oxygen site may serve as nucleation centers for small Pt clusters grown on bare TiO2 NT. The density of states and adsorption analysis indicate that the adsorption of Ptn cluster on bare TiO2 NT narrows the optical energy gap. The redshift in the adsorption spectra occurred.