Kobkeatthawin Thawanrat, Chaveanghong Suwilai, Trakulmututa Jirawat, Amornsakchai Taweechai, Kajitvichyanukul Puangrat, Smith Siwaporn Meejoo
Center of Sustainable Energy and Green Materials and Department of Chemistry, Faculty of Science, Mahidol University, 999 Phuttamonthon Sai 4 Road, Salaya, Nakhon Pathom 73170, Thailand.
Center of Excellence for Innovation in Chemistry, 272 Rama VI Road, Rajthevi, Bangkok 10400, Thailand.
Nanomaterials (Basel). 2022 Aug 18;12(16):2852. doi: 10.3390/nano12162852.
This research employed g-CN nanosheets in the hydrothermal synthesis of TiO/g-CN hybrid photocatalysts. The TiO/g-CN heterojunctions, well-dispersed TiO nanoparticles on the g-CN nanosheets, are effective photocatalysts for the degradation of monochlorophenols (MCPs: 2-CP, 3-CP, and 4-CP) which are prominent water contaminants. The removal efficiency of 2-CP and 4-CP reached 87% and 64%, respectively, after treatment of 25 ppm CP solutions with the photocatalyst (40TiO/g-CN, 1 g/L) and irradiation with UV-Vis light. Treatment of CP solutions with g-CN nanosheets or TiO alone in conjunction with irradiation gave removal efficiencies lower than 50%, which suggests the two act synergically to enhance the photocatalytic activity of the 40TiO/g-CN nanocomposite. Superoxide and hydroxyl radicals are key active species produced during CP photodegradation. In addition, the observed nitrogen and Ti defects and oxygen vacancies in the TiO/g-CN nanocomposites may improve the light-harvesting ability of the composite and assist preventing rapid electron-hole recombination on the surface, enhancing the photocatalytic performance. In addition, interfacial interactions between the MCPs (low polarity) and thermally exfoliated carbon nitride in the TiO/g-CN nanocomposites may also enhance MCP degradation.
本研究采用g-CN纳米片通过水热合成法制备TiO/g-CN复合光催化剂。TiO/g-CN异质结是在g-CN纳米片上均匀分散的TiO纳米颗粒，是降解作为主要水体污染物的单氯酚（MCPs：2-氯酚、3-氯酚和4-氯酚）的有效光催化剂。在用光催化剂（40TiO/g-CN，1 g/L）处理25 ppm的氯酚溶液并进行紫外-可见光照射后，2-氯酚和4-氯酚的去除效率分别达到了87%和64%。单独使用g-CN纳米片或TiO处理氯酚溶液并结合照射，去除效率低于50%，这表明二者协同作用可提高40TiO/g-CN纳米复合材料的光催化活性。超氧自由基和羟基自由基是氯酚光降解过程中产生的关键活性物种。此外，在TiO/g-CN纳米复合材料中观察到的氮和钛缺陷以及氧空位可能会提高复合材料的光捕获能力，并有助于防止表面电子-空穴的快速复合，从而增强光催化性能。此外，MCPs（低极性）与TiO/g-CN纳米复合材料中热剥离的氮化碳之间的界面相互作用也可能增强MCPs的降解。
