Al-Sabahi Jamal, Bora Tanujjal, Al-Abri Mohammed, Dutta Joydeep
Department of Chemical and Petroleum Engineering, College of Engineering, Sultan Qaboos University, PO Box 33, PC 123, Al-Khoudh, Oman.
Chair in Nanotechnology, Water Research Center, Sultan Qaboos University, PO Box 17, PC 123, Al-Khoudh, Oman.
Materials (Basel). 2016 Mar 28;9(4):238. doi: 10.3390/ma9040238.
Environmental pollution from human and industrial activities has received much attention as it adversely affects human health and bio-diversity. In this work we report efficient visible light photocatalytic degradation of phenol using supported zinc oxide (ZnO) nanorods and explore the role of surface defects in ZnO on the visible light photocatalytic activity. ZnO nanorods were synthesized on glass substrates using a microwave-assisted hydrothermal process, while the surface defect states were controlled by annealing the nanorods at various temperatures and were characterized by photoluminescence and X-ray photoelectron spectroscopy. High performance liquid chromatography (HPLC) was used for the evaluation of phenol photocatalytic degradation. ZnO nanorods with high surface defects exhibited maximum visible light photocatalytic activity, showing 50% degradation of 10 ppm phenol aqueous solution within 2.5 h, with a degradation rate almost four times higher than that of nanorods with lower surface defects. The mineralization process of phenol during degradation was also investigated, and it showed the evolution of different photocatalytic byproducts, such as benzoquinone, catechol, resorcinol and carboxylic acids, at different stages. The results from this study suggest that the presence of surface defects in ZnO nanorods is crucial for its efficient visible light photocatalytic activity, which is otherwise only active in the ultraviolet region.
人类活动和工业活动造成的环境污染因其对人类健康和生物多样性产生不利影响而备受关注。在本研究中，我们报道了负载型氧化锌（ZnO）纳米棒对苯酚的高效可见光光催化降解，并探讨了ZnO表面缺陷在可见光光催化活性中的作用。采用微波辅助水热法在玻璃基底上合成了ZnO纳米棒，通过在不同温度下对纳米棒进行退火处理来控制表面缺陷态，并利用光致发光和X射线光电子能谱对其进行表征。采用高效液相色谱（HPLC）对苯酚的光催化降解进行评估。具有高表面缺陷的ZnO纳米棒表现出最大的可见光光催化活性，在2.5小时内可使10 ppm苯酚水溶液降解50%，降解速率几乎是表面缺陷较低的纳米棒的四倍。还研究了苯酚降解过程中的矿化过程，结果表明在不同阶段会生成不同的光催化副产物，如苯醌、邻苯二酚、间苯二酚和羧酸。本研究结果表明，ZnO纳米棒表面缺陷的存在对其高效可见光光催化活性至关重要，否则它仅在紫外区域具有活性。
