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提高TiO2光催化活性已成为近年研究的热点。选取第一过渡金属Cu与Cr共同掺杂金红石相TiO2,运用基于密度泛函理论体系下的平面波超软赝势方法探讨了Cu-Cr共掺杂对金红石相TiO2电子特性和光学性质影响的微观机制。结果表明:Cu-Cr共掺杂TiO2在禁带中形成了5条新的杂质能级,其中价带顶的一条杂质能级主要是Cu3d轨道的贡献,而费米面附近的4条亚稳态杂质能级主要由Cr3d轨道和O2p轨道相互作用产生,有效减小了电子的跃迁能,改善了TiO2的光催化活性。Cu-Cr共掺杂也改善了TiO2的光学性质,使光谱红移,反射率增大,对可见光的吸收和反射能力比单掺杂更稳定。
Increasing the TiO2 photocatalytic activity has become a hot spot in recent years. The first transition metal Cu and Cr were co-doped with rutile TiO2. The effects of Cu-Cr co-doping on the electronic and optical properties of the rutile TiO2 were investigated by the plane wave super soft pseudopotential method based on density functional theory mechanism. The results show that Cu-Cr co-doped TiO2 forms five new impurity levels in the forbidden band, in which one impurity level at the top of the valence band contributes mainly to the Cu3d orbital while the four metastable states near the Fermi level The impurity level is mainly caused by the interaction between the Cr3d orbit and the O2p orbit, effectively reducing the electron transition energy and improving the photocatalytic activity of TiO2. Cu-Cr co-doping also improves the optical properties of TiO2, redshifts the spectrum, increases the reflectivity, and has a more stable absorption and reflection of visible light than single doping.