Subtle structure matters: boosting surface-directed photoelectron transfer via the introduction of specific monovalent oxygen vacancies in TiO2
Subtle structure matters: boosting surface-directed photoelectron transfer via the introduction of specific monovalent oxygen vacancies in TiO2
复制标题
微妙的结构很重要：通过在 TiO2 中引入特定的单价氧空位来促进表面定向光电子转移
DOI：
10.1039/d1cp02787e
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发表时间：
2021
影响因子：
3.3
通讯作者：
Gong Xue-Qing
中科院分区：
文献类型：
--
作者：
Li Fei;Wang Dong;Gong Xue-Qing
氧空位(Ov)被广泛认为在光催化中起着至关重要的作用，但它们如何以及为什么有助于提高性能仍然存在争议。在这项工作中，我们用第一性原理密度泛函理论计算并修正了现场库仑相互作用，研究了Ov对TiO2光电子转移的促进作用。通过电子结构分析，我们明确地确定了三种不同电荷状态(即电荷中性、一价、二价Ov2+)的Ov。电子转移能计算表明，锐钛矿型二氧化钛中的电离Ov能够收集多余的电子，而金红石相中的电离Ov则不能。电离Ov的存在进一步赋予锐钛矿型TiO2光催化剂沿[100]方向的定向电子转移，有利于锐钛矿型TiO2光催化还原超过(001)晶面的终止。在考察了涉及不同电荷态和空间分布的电离Ov的各种组合模式后，我们证明了锐钛矿型TiO2101中的垂直链是TiO2中最有效的Ov模式。这些结果表明了光催化中细微缺陷的重要性，并可能有助于未来光催化剂的设计以获得更高的光催化效率。
Oxygen vacancies (Ov) are widely considered to play crucial roles in photocatalysis, but how and why they contribute to improved performances remains controversial. In this work, we studied the promotional effect of Ov on photoelectron transfer in TiO2, using first-principles density functional theory calculations with correction for on-site Coulomb interactions. We explicitly identified three types of Ov with different charge states (i.e., charge-neutral , monovalent , divalent Ov2+) via electronic structure analysis. Electron transfer energy calculations revealed that the ionized Ov in anatase TiO2 are able to collect excess electrons whereas those in the rutile phase are not. The presence of ionized Ov further endows anatase TiO2 with directional electron transfer along the [100] orientation, in favor of anatase TiO2(101) for photocatalytic reduction surpassing the (001) termination. After examining various combination modes of ionized Ov involving different charge states and spatial distributions, we demonstrated that the vertical chain in anatase TiO2(101) is the most catalytically effective Ov pattern in TiO2. These results signify the importance of subtle defects in photocatalysis and may assist future photocatalyst design toward higher photocatalytic efficiency.