Liu Li, Ouyang Ping, Li Yuhan, Duan Youyu, Dong Fan, Lv Kangle
Engineering Research Center for Waste Oil Recovery Technology and Equipment, Ministry of Education, Chongqing Key Laboratory of Catalysis and New Environmental Materials, Chongqing Technology and Business University, Chongqing 400067, China.
Engineering Research Center for Waste Oil Recovery Technology and Equipment, Ministry of Education, Chongqing Key Laboratory of Catalysis and New Environmental Materials, Chongqing Technology and Business University, Chongqing 400067, China.
J Hazard Mater. 2022 Oct 5;439:129637. doi: 10.1016/j.jhazmat.2022.129637. Epub 2022 Jul 21.
Deeply photocatalytic oxidation of nitrogen oxides is still difficult to achieve, mainly limited by few intrinsic active sites and inefficient carrier separation of photocatalysts. Accordingly, we develop a simple room temperature tactic to introduce oxygen vacancies (OVs) into BiTaO (BTO). Based on solid experimental and DFT theoretical supports, we explore the mechanism of NO removal over OVs decorated BTO (OVs-BTO). OVs can not only alter the distribution of local electrons to result in the formation of a fast charge transfer channel between OVs and the adjacent Ta atoms, which improves the transport rate of photogenerated carriers; but also function as active sites to adsorb small molecules (NO, O and HO), which being activated and positively drive the NO oxidation reaction. In order to investigate a possible reaction path, a combination of in-situ DRIFTS and simulated Gibbs free energy reveals that the intermediate products of OVs-BTO are helpful to promote the deep oxidation of NO to NO, while pristine BTO is more likely to produce NO intermediate toxic by-products, which greatly hinders the deep photocatalytic oxidation of NO. This work provides insights into the role of OVs in photocatalysts, and also points out a guideline for the mechanism of semiconductor photocatalysts in eliminating gaseous pollutants.
氮氧化物的深度光催化氧化仍然难以实现，主要受限于光催化剂的本征活性位点较少以及载流子分离效率低下。因此，我们开发了一种简单的室温策略，将氧空位（OVs）引入到BiTaO（BTO）中。基于坚实的实验和DFT理论支持，我们探究了OVs修饰的BTO（OVs-BTO）上NO去除的机理。OVs不仅可以改变局部电子的分布，导致在OVs和相邻Ta原子之间形成快速电荷转移通道，从而提高光生载流子的传输速率；还可以作为活性位点吸附小分子（NO、O和HO），这些小分子被激活并积极推动NO氧化反应。为了研究可能的反应路径，原位DRIFTS和模拟吉布斯自由能相结合表明，OVs-BTO的中间产物有助于促进NO深度氧化为NO，而原始的BTO更有可能产生NO中间有毒副产物，这极大地阻碍了NO的深度光催化氧化。这项工作深入了解了OVs在光催化剂中的作用，也为半导体光催化剂消除气态污染物的机理指出了一条指导方针。
