锐钛矿型 TiO2 中掺杂剂电子和光学性质的杂化功能研究,ACS Omega

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锐钛矿型 TiO2 中掺杂剂电子和光学性质的杂化功能研究
ACS Omega ( IF 3.7 ) Pub Date : 2023-10-31 , DOI: 10.1021/acsomega.3c04329
W A Chapa Pamodani Wanniarachchi _{1,

2} , Thevakaran Arunasalam ₁ , Punniamoorthy Ravirajan ₁ , Dhayalan Velauthapillai ₂ , Ponniah Vajeeston ₃

Affiliation

TiO ₂因其化学稳定性好、成本低、无毒、氧化能力强而被称为金色多相光催化剂。然而，锐钛矿型TiO ₂主要吸收紫外区（λ < 387.5 nm）的光子能量；因此，为了提高太阳光的利用率，采用了在纯TiO _{2中掺杂金属和非金属的方法。}在这里，我们将 Zr、Si、V、W、Ge、Cr、Sn、Mo 和 Pb 的掺杂剂掺入 TiO ₂晶格中，并使用维也纳从头算法研究光电特性，包括形成能和电子电荷分布。来自 Heyd、Scuseria 和 Erhzerhof (HSE06) 混合功能的仿真包 (VASP)。我们观察到 V、Mo 和 Cr 掺杂系统在带隙内引入了浅杂质态，这些态通过提高光催化效率来影响吸收光谱向可见光的转变。W掺杂的锐钛矿型TiO _{2结构使纯锐钛矿型TiO}₂的带隙降低了0.7eV。值得注意的是，这种减少在带边缘之间没有引入任何杂质态的情况下发生。此外，太阳光谱的吸收边从 3.5 eV 向较低光子能量移动至 3.1 eV。从Bader电荷分析中，我们观察到电荷转移主要发生在掺杂剂上，电荷积累发生在附近的氧原子周围。由于自旋向上和自旋向下状态的电荷不平衡，在 V、Cr、Mo 和 W 掺杂锐钛矿 TiO ₂结构中观察到铁磁性。

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Hybrid Functional Study on Electronic and Optical Properties of the Dopants in Anatase TiO2

TiO₂ was known as a golden heterogeneous photocatalyst due to its chemical stability, low cost, nontoxicity, and strong oxidizing power. However, anatase TiO₂ predominantly absorbs the photon energy in the ultraviolet region (λ < 387.5 nm); therefore, to increase the utilization of sunlight, the approach of doping of metals and nonmetals into pure TiO₂ is implemented. Here we incorporate the dopants of Zr, Si, V, W, Ge, Cr, Sn, Mo, and Pb into the TiO₂ lattice and study the optoelectronic properties, including the formation energies and the electron charge distributions, using the Vienna ab initio Simulation Package (VASP) from the hybrid functional of Heyd, Scuseria, and Erhzerhof (HSE06). We observed that V-, Mo-, and Cr-doped systems introduce shallow impurity states within the band gap, and those states influence the shift of the absorbance spectra to visible light by enhancing the photocatalytic efficiency. W-doped anatase TiO₂ structure reduces the band gap of the pure anatase TiO₂ by 0.7 eV. Notably, this reduction occurs without the introduction of any impurity states between the band edges. Additionally, the absorption edge of the solar spectrum shifts toward lower photon energy from 3.5 to 3.1 eV. From Bader charge analysis, we observed that mainly the charge transfer occurred from the dopants and charge accumulation happened around nearby oxygen atoms. The ferromagnetism was observed in V-, Cr-, Mo-, and W-doped anatase TiO₂ structures due to the charge imbalance of the spin-up and spin-down states.

更新日期：2023-10-31

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