Lei Ben, Cui Wen, Sheng Jianping, Wang Hong, Chen Peng, Li Jieyuan, Sun Yanjuan, Dong Fan
Chongqing Key Laboratory of Catalysis and New Environmental Materials, College of Environment and Resources, Chongqing Technology and Business University, Chongqing 400067, China; Research Center for Environmental Science & Technology, Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 611731, China.
Chongqing Key Laboratory of Catalysis and New Environmental Materials, College of Environment and Resources, Chongqing Technology and Business University, Chongqing 400067, China; The Center of New Energy Materials and Technology, School of Materials Science and Engineering, Southwest Petroleum University, Chengdu 610500, China.
Sci Bull (Beijing). 2020 Mar 30;65(6):467-476. doi: 10.1016/j.scib.2020.01.007. Epub 2020 Jan 10.
This work unraveled the synergistic effects of crystal structure and oxygen vacancy on the photocatalytic activity of BiO polymorphs at an atomic level for the first time. The artificial oxygen vacancy is introduced into α-BiO and β-BiO via a facile method to engineer the band structures and transportation of carriers and redox reaction for highly enhanced photocatalysis. After the optimization, the photocatalytic NO removal ratio on defective β-BiO was increased from 25.2% to 52.0% under visible light irradiation. On defective α-BiO, the NO removal ratio is just increased from 7.3% to 20.1%. The difference in the activity enhancement is associated with the different structure of crystal phase and oxygen vacancy. The density functional theory (DFT) calculation and experimental results confirm that the oxygen vacancy in α-BiO and β-BiO could promote the activation of reactants and intermediate as active centers. The crystal structure and oxygen vacancy could synergistically regulate the electrons transfer pathway. On defective β-BiO with tunnel structure, the reactants activation and charge transfer were more efficient than that on α-BiO with zigzag-type configuration because the defect structures on the surface of α-BiO and β-BiO were different. Moreover, the in situ FT-IR revealed the mechanisms of photocatalytic NO oxidation. The photocatalytic NO conversion pathway on α-BiO and β-BiO can be tuned by the different surface defect structures. This work could provide a novel strategy to regulate the photocatalytic activity and conversion pathway via the synergistic effects of crystal structure and oxygen vacancy.
这项工作首次在原子水平上揭示了晶体结构和氧空位对BiO多晶型物光催化活性的协同作用。通过一种简便的方法将人工氧空位引入α-BiO和β-BiO中，以设计能带结构、载流子传输和氧化还原反应，从而实现光催化性能的高度增强。经过优化，在可见光照射下，缺陷型β-BiO上的光催化NO去除率从25.2%提高到了52.0%。在缺陷型α-BiO上，NO去除率仅从7.3%提高到了20.1%。活性增强的差异与晶相结构和氧空位的不同有关。密度泛函理论（DFT）计算和实验结果证实，α-BiO和β-BiO中的氧空位可以促进反应物和中间体的活化，作为活性中心。晶体结构和氧空位可以协同调节电子转移途径。在具有隧道结构的缺陷型β-BiO上，反应物的活化和电荷转移比具有锯齿形构型的α-BiO更有效，因为α-BiO和β-BiO表面的缺陷结构不同。此外，原位傅里叶变换红外光谱揭示了光催化NO氧化的机理。α-BiO和β-BiO上的光催化NO转化途径可以通过不同的表面缺陷结构进行调控。这项工作可以提供一种新的策略，通过晶体结构和氧空位的协同作用来调节光催化活性和转化途径。
