Liu Baoshun, Wang Jiangyan, Parkin Ivan P, Zhao Xiujian
State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan City, Hubei province 430070, P. R. China.
Phys Chem Chem Phys. 2021 Apr 14;23(14):8300-8308. doi: 10.1039/d1cp00118c. Epub 2021 Mar 30.
Modifying TiO with the Cu element has been shown to be useful for photocatalysis. Although it had been known that Cu species could trap electrons from TiO, whether they can affect the kinetics of electron transfer and how this can contribute to photocatalysis still remain unknown. In the current research, Cu-TiO samples were firstly prepared with a hydrothermal reaction and characterized in detail. It was shown that Cu elements were doped in the TiO lattice in +1/0 valence states and have a minor effect on the TiO structure. By means of photoconductances, it is shown that the Cu dopants could catalyze the electron transfer from TiO to O by reducing the apparent activation energy (E) by about 2 times. The photocatalytic experiments conducted at different temperatures showed that the E of the acetone photocatalytic oxidations could be decreased by ∼2 times; this implies that the Cu dopants change the photocatalytic pathway. First-principles computation showed that the surface Cu dopants, along with the compensated oxygen vacancies, can mediate both of the electron and hole transfer. By combining other studies, we proposed that the Cu sites could act as Lewis acid and base pairs that could combine with acetone and O molecules under UV light illumination; this allows electron transfer to Ovia the Cu sites that then react with acetone. As compared to pure TiO surfaces, the different chemical environment of the Cu sites leads to the decrease in the E of photocatalysis.
已证明用铜元素修饰二氧化钛对光催化很有用。尽管已知铜物种可以从二氧化钛捕获电子，但它们是否会影响电子转移动力学以及这如何促进光催化仍然未知。在当前研究中，首先通过水热反应制备了铜 - 二氧化钛样品并进行了详细表征。结果表明，铜元素以 +1/0 价态掺杂在二氧化钛晶格中，对二氧化钛结构影响较小。通过光导测量表明，铜掺杂剂可以通过将表观活化能（E）降低约 2 倍来催化电子从二氧化钛转移到氧。在不同温度下进行的光催化实验表明，丙酮光催化氧化的 E 可以降低约 2 倍；这意味着铜掺杂剂改变了光催化途径。第一性原理计算表明，表面铜掺杂剂与补偿的氧空位一起，可以介导电子和空穴的转移。结合其他研究，我们提出铜位点可以作为路易斯酸碱对，在紫外光照射下可以与丙酮和氧分子结合；这使得电子通过铜位点转移到氧，然后与丙酮反应。与纯二氧化钛表面相比，铜位点不同的化学环境导致光催化的 E 降低。
