Mg0.8Zn0.2O Microspheres: Preparation, Characterization and Application for Degrading Organic Dyes
Mg0.8Zn0.2O Microspheres: Preparation, Characterization and Application for Degrading Organic Dyes
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Mg0.8Zn0.2O微球的制备、表征及降解有机染料的应用
DOI：
10.1039/c9ce01717h
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发表时间：
--
期刊：
影响因子：
3.1
通讯作者：
Zhiping Zhang
中科院分区：
文献类型：
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作者：
Yajun Zheng;Liyun Cao;Gaoxuan Xing;Jianfeng Huang;Zhiping Zhang
光催化降解废水中的有机污染物是最有前途的环境修复策略之一，而光催化剂作为其先决条件受到了广泛的关注。本文报道了利用CO 32-、Mg 2+和Zn 2+反应制备的直径约为36 μm的Mg0.8Zn0.2O微球对有机染料的高效、无毒、廉价降解。Mg 2+和Zn 2+之间的摩尔比被发现在确定所得产物的形貌和光催化性能中起着至关重要的作用。根据时间相关实验，提出了球形Mg 0. 8 Zn 0. 2 O复合材料的可能形成机制，即首先形成由细粉组成的不规则团聚体，然后转变为棒状结构。由于其热不稳定性，棒状颗粒经历进一步的自组装，并成为更稳定的球形产物，ZnCO 3嵌入Mg 5（CO 3）4（OH）2·4 H2O片层之间的空间。在研究光催化性能之后，结果表明，所开发的Mg 0.8Zn 0.2O复合物不仅在紫外光或可见光照射下降解有机染料方面上级其他现有技术的催化剂如P25 TiO 2和g-C3 N4，而且是一种两性光催化剂，在强酸性（pH 2-4）和强碱性（pH 12）溶液中均更有利于降解有机染料。此外，它的催化效率保持高达98.3%，经过6个循环。这些特点使得开发的Mg0.8Zn0.2O复合材料在实际应用中的有机染料的处理前景。进一步的实验，包括光致发光，吸附和光电化学测量占基本的光催化机理的Mg0.8Zn0.2O复合材料降解有机染料。
Photocatalytic degradation of organic pollutants in wastewater is one of the most promising strategies for environmental remediation, and photocatalysts as the prerequisite have received considerable attention. Herein we reported highly efficient, nontoxic, and inexpensive Mg0.8Zn0.2O microspheres with a diameter of around 36 μm prepared through reaction between CO32−, Mg2+ and Zn2+ for degrading organic dyes. The molar ratio between Mg2+ and Zn2+ was found to play a crucial role in determining the morphology and photocatalytic performance of the resulting product. According to time-dependent experiments, the plausible formation mechanism for the spherical-like Mg0.8Zn0.2O composite was proposed, in which irregular agglomerates composed of fine powders were first formed followed by their transformation into rod-like structures. Due to their thermal instability, the rod-like particles underwent further self-assembly and became a more stable spherical-like product with ZnCO3 embedded in the space between Mg5(CO3)4(OH)2·4H2O sheets. After investigating the photocatalytic performance, the results demonstrated that the developed Mg0.8Zn0.2O composite was not only superior to other state-of-the-art catalysts such as P25 TiO2 and g-C3N4 in degrading organic dyes upon irradiation under either UV light or visible light, but also was an amphoteric photocatalyst more favorable for degrading organic dyes in both strongly acidic (pH 2–4) and strongly alkaline (pH 12) solutions. Moreover, its catalytic efficiency remained as high as 98.3% after six cycles. These features made the developed Mg0.8Zn0.2O composite promising in practical utilization for treatment of organic dyes. Further experiments including photoluminescence, adsorption and photoelectrochemical measurements accounted for the underlying photocatalytic mechanism of the Mg0.8Zn0.2O composite for degradation of organic dyes.