Zhang Shengqiang, Su Changsheng, Ren Hang, Li Mengli, Zhu Longfeng, Ge Shuang, Wang Min, Zhang Zulei, Li Lei, Cao Xuebo
College of Biological, Chemical Sciences and Engineering, Jiaxing University, 118 Jiahang Road, Jiaxing 314001, China.
Department of Chemical and Biomolecular Engineering, University of Notre Dame, IN 46556, USA.
Nanomaterials (Basel). 2019 Feb 6;9(2):215. doi: 10.3390/nano9020215.
The nanocomposite preparation procedure plays an important role in achieving a well-established heterostructured junction, and hence, an optimized photocatalytic activity. In this study, a series of g-C₃N₄/ZnO nanocomposites were prepared through two distinct procedures of a low-cost, environmentally-friendly, in-situ fabrication process, with urea and zinc acetate being the only precursor materials. The physicochemical properties of synthesized g-C₃N₄/ZnO composites were mainly characterized by XRD, UV⁻VIS diffuse reflectance spectroscopy (DRS), N₂ adsorption-desorption, FTIR, TEM, and SEM. These nanocomposites' photocatalytic properties were evaluated in methylene blue (MB) dye photodecomposition under UV and sunlight irradiation. Interestingly, compared with ZnO nanorods, g-C₃N₄/ZnO nanocomposites (:1, obtained from urea and ZnO nanorods) exhibited weak photocatalytic activity likely due to a "shading effect", while nanocomposites (:1 CN, made from g-C₃N₄ and zinc acetate) showed enhanced photocatalytic activity that can be ascribed to the effective establishment of heterojunctions. A kinetics study showed that a maximum reaction rate constant of 0.1862 min can be achieved under solar light illumination, which is three times higher than that of bare ZnO nanorods. The photocatalytic mechanism was revealed by determining reactive species through adding a series of scavengers. It suggested that reactive ∙O₂ and h⁺ radicals played a major role in promoting dye photodegradation.
纳米复合材料的制备过程对于实现良好的异质结构结至关重要，因此对于优化光催化活性也很重要。在本研究中，通过低成本、环境友好的原位制备工艺的两种不同方法制备了一系列g-C₃N₄/ZnO纳米复合材料，仅使用尿素和醋酸锌作为前驱体材料。合成的g-C₃N₄/ZnO复合材料的物理化学性质主要通过XRD、紫外可见漫反射光谱（DRS）、N₂吸附-脱附、FTIR、TEM和SEM进行表征。在紫外光和太阳光照射下，通过亚甲基蓝（MB）染料光分解评估了这些纳米复合材料的光催化性能。有趣的是，与ZnO纳米棒相比，g-C₃N₄/ZnO纳米复合材料（：1，由尿素和ZnO纳米棒制备）由于“遮蔽效应”表现出较弱的光催化活性，而纳米复合材料（：1 CN，由g-C₃N₄和醋酸锌制备）表现出增强的光催化活性，这可归因于异质结的有效形成。动力学研究表明，在太阳光照射下可实现最大反应速率常数为0. min，这是裸ZnO纳米棒的三倍。通过添加一系列清除剂确定活性物种揭示了光催化机理。结果表明，活性∙O₂和h⁺自由基在促进染料光降解中起主要作用。
