Density functional study of X monodoped and codoped (X=C, N, S, F) anatase TiO2
Density functional study of X monodoped and codoped (X=C, N, S, F) anatase TiO2
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DOI：
10.1016/j.commatsci.2014.06.035
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发表时间：
2013-11
期刊：
影响因子：
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通讯作者：
Pengyu Dong;Huanhuan Pei;Qinfang Zhang;Yuhua Wang
中科院分区：
文献类型：
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作者：
Pengyu Dong;Huanhuan Pei;Qinfang Zhang;Yuhua Wang
采用密度泛函理论，在广义梯度修正近似下，研究了非金属杂质X(X~(2+)=C，N，S，F)取代锐钛矿型二氧化钛中O位或钛位的模型。通过计算X取代O的X掺杂二氧化钛的形成能，我们认为X掺杂分别以C4−、N3−、S2−和F−离子的形式存在。同时，对于X取代钛的X-单晶(X=0.C，N，S)TiO2，X掺杂以C4+、N3+和S6+形式存在。优化晶胞参数和局域结构的结果也支持了非金属杂质X取代TiO2中O或Ti位的价态的结论。此外，还提出了一种有效的非金属钝化共掺杂方法来修饰TiO2的带边。基于第一性原理计算，我们认为非金属钝化基团(S2−+和C4+)和(C4−+和S6+)可以大幅度地缩小带隙，使导带极小值产生较小的扰动，从而在不影响还原功率的情况下获得理想的可见光吸收区域。这项工作提供了一些新的结果，期望对设计高效的可见光驱动TiO2光催化剂具有一定的启发和指导作用。
Using density-functional theory (DFT) calculations within the generalized gradient corrected approximation, the models that nonmetallic impurities X (X = C, N, S, F) substituted for O or Ti sites in anatase TiO2were investigated. By calculating the formation energy of X-monodoped TiO2with X substituted for O, we suggested that X dopants existed as C4−, N3−, S2−and F−ions, respectively. Meanwhile, the X dopants existed as C4+, N3+, and S6+for X-monodoped (X = C, N, S) TiO2with X substituted for Ti. The conclusion of the valence states of nonmetallic impurities X substituted for O or Ti sites in TiO2is also supported by the results of optimized cell parameters and the local structures. Furthermore, an effective nonmetallic passivated codoping approach to modify the band edges of TiO2is proposed. Based on the first-principle calculations, we suggested that nonmetallic passivated groups such as (S2−+ C4+) and (C4−+ S6+) could reduce the band gap largely and make less perturbation in conduction band minima (CBM), thus lead to an ideal visible-light absorption region without affecting the reducing power. This work provides some new results and is anticipated to give some inspiration and guidance for design visible-light-driven TiO2photocatalyst with high efficiency.