Significantly Enhanced Photocatalytic Activities and Charge Separation Mechanism of Pd-Decorated ZnO-Graphene Oxide Nanocomposites
Significantly Enhanced Photocatalytic Activities and Charge Separation Mechanism of Pd-Decorated ZnO-Graphene Oxide Nanocomposites
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Pd修饰的ZnO-氧化石墨烯纳米复合材料显着增强的光催化活性和电荷分离机制
DOI：
10.1021/am405872r
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发表时间：
2014
影响因子：
9.5
通讯作者：
Mai Wenjie
中科院分区：
文献类型：
--
作者：
Zhang Long;Du Lianhuan;Yu Xiang;Tan Shaozao;Cai Xiang;Yang Peihua;Gu Yu;Mai Wenjie
电子-空穴复合是制约zno基光催化剂效率的主要因素之一。在这项工作中，采用2倍增强策略来抑制电子-空穴复合并提高光催化效率。首先，系统地研究了氧化石墨烯（GO）对ZnO光催化活性的显著增强。合成了不同ZnO与GO质量比（0.95:0.05 ~ 0.70:0.30）的杂化光催化剂，并对其进行了表征。结果表明，当氧化锌与氧化石墨烯的比例达到0.85:0.15时，合成的ZnO - GO纳米复合材料对亚甲基蓝的光催化效率最高，其表观速率常数约为纯ZnO的10倍。由于氧化石墨烯具有很强的染料吸附和电荷分离能力，因此被认为可以增强ZnO的光催化活性。其次，引入Pd纳米粒子修饰ZnO-GO，制备出性能普遍较好的光催化剂ZnO-GO - Pd纳米复合材料。由于金属半导体二极管效应，Pd和ZnO之间的结被认为也有效地分离了光产生的电荷。这两种体系的ZnO-GO和ZnO-GO - pd纳米复合材料在环境保护方面具有广泛的应用前景。
Electron–hole recombination is one of the major factors limiting the efficiency of ZnO-based photocatalysts. In this work, a 2-fold enhancement strategy was employed to suppress electron–hole recombination and boost photocatalytic efficiency. First, significantly enhanced photocatalytic activity of ZnO by introducing graphene oxide (GO) was systematically investigated. Hybrid photocatalysts with different weight ratios of ZnO to GO (from 0.95:0.05 to 0.70:0.30) were synthesized and characterized. The results indicated that when the proportion ratio of ZnO to GO reached 0.85:0.15, the as-synthesized ZnO–GO nanocomposite exhibited the maximum photocatalytic efficiency on methylene blue with an apparent rate constant κappalmost 10 times faster than that of pure ZnO under UV illumination. GO was suggested to enhance the photocatalytic activity of ZnO because of its great capability in dye adsorption and charge separation. Second, Pd nanoparticles were introduced to decorate ZnO–GO to produce generally better photocatalyst ZnO–GO–Pd nanocomposites. The junction between Pd and ZnO was believed to also effectively separate the photogenerated charges due to the metal-semiconductor diode effect. These two systems of ZnO–GO and ZnO–GO–Pd nanocomposites are expected to have a broad range of applications in environmental conservation.