ZnS微球的水热/溶剂热法合成及其光催化性能研究

doi:10.15541/jim20150508

摘要/Abstract

摘要：

采用水热/溶剂热法, 以Zn(Ac)₂·2H₂O和 CH₄N₂S为反应物合成ZnS微球。对ZnS微球进行X射线衍射(XRD)、扫描电镜(SEM)及紫外可见漫反射光谱等表征。结果表明, 合成的ZnS微球为立方闪锌矿型晶体结构, 由ZnS纳米粒子自组装而成。在降解苯酚水溶液的光催化研究中, 以乙二醇-水为溶剂合成的ZnS光催化活性明显优于其他溶剂体系合成的ZnS, 循环使用3次仍保持较高的活性。ZnS微球光催化性能的提高可归结为以下三方面的协同作用: 较小的禁带宽度(3.39 eV)有利于吸收光子, 较完整的晶体结构使催化剂活性分子数增多和较大的比表面积(19.4 m²/g)有利于反应液与催化剂的充分接触。ZnS微球降解苯酚的中间产物为乙二酸、顺丁烯二酸和极少量的对苯二酚。

关键词: 水热/溶剂热法, 自组装, ZnS微球, 苯酚, 光催化

Abstract:

ZnS microspheres were synthesized via hydrothermal/solvothermal method using Zn(Ac)₂·2H₂O and CH₄N₂S as reactants. ZnS was characterized by XRD, SEM and UV-Vis diffuse reflectance spectrum. The results showed that as-synthesized ZnS microspheres had zinc blende crystalline structure which was self-assembled by small ZnS nanoparticles. As for the photocatalytic degradation of phenol aqueous solution, ZnS microspheres synthesized in (CH₂OH)₂-H₂O system revealed much better photocatalytic activity than that of ZnS synthesized in other solvent systems, and it kept high activity after cycling degradation for 3 times. The enhanced photocatalytic performance of ZnS microspheres could be attributed to the cooperation effect of the following three aspects: the smaller band gap (3.39 eV) being conducive to the absorption of photons, the more complete crystal structure to increase the number of active molecules, and larger specific surface area (19.4 m²/g) being in favor of sufficient contacting between the reaction solution, and the catalyst. The intermediate products were oxalic acid, maleic acid and very little hydroquinone in photocatalytic degradation of phenol by ZnS microspheres.

Key words: hydrothermal/solvothermal method, self-assembly, ZnS microsphere, phenol, photocatalysis

中图分类号:

O643

武萱蓉, 杨巧珍, 赵永祥, 路艳罗. ZnS微球的水热/溶剂热法合成及其光催化性能研究[J]. 无机材料学报, 2016, 31(5): 473-478.

WU Xuan-Rong, YANG Qiao-Zhen, ZHAO Yong-Xiang, LU Yan-Luo. Hydrothermal/Solvothermal Synthesis and Photocatalytic Performance of ZnS Microspheres[J]. Journal of Inorganic Materials, 2016, 31(5): 473-478.

图/表 7

图1 不同溶剂体系合成ZnS的XRD图谱

Fig. 1 XRD patterns of as-synthesized ZnS in different solvent systems (a) (CH2OH)2; (b) (CH2OH)2-H2O; (c) H2O

图2 不同溶剂体系合成ZnS的SEM和HRTEM照片

Fig. 2 SEM ( a, b, c) and HRTEM images (e, f, g) of as-synthesized ZnS in different solvent systems (a, d) (CH2OH)2; (b, e) (CH2OH)2-H2O; (c, f) H2O

图3 不同溶剂体系合成ZnS的UV-Vis漫反射光谱图

Fig. 3 UV-Vis diffuse reflectance spectra of as-synthesized ZnS in different solvent systems (a) (CH2OH)2; (b) (CH2OH)2-H2O; (c) H2O

图4 不同溶剂体系合成ZnS的光学带隙的(αhν)2-hν曲线

Fig. 4 (αhν)2 vs hν for determinging optical band gap of as-sythesized ZnS in different solvent systems (a) (CH2OH)2; (b) (CH2OH)2-H2O; (c) H2O

图5 不同溶剂体系合成的ZnS光催化降解苯酚性能

Fig. 5 Phenol photocatalytic degradation performance of as-synthesized ZnS in different solvent systems (a) (CH2OH)2, 0 W; (b) 300 W; (c) (CH2OH)2, 300 W; (d) (CH2OH)2-H2O, 300 W ; (e) H2O, 300 W

图6 ZnS光催化降解苯酚的循环实验

Fig. 6 Phenol degradation cycling tests of ZnS

图7 苯酚及其中间产物的质量浓度随时间的变化规律

Fig. 7 Evolution of phenol and intermediate products with time (a) Phenol; (b) Maleic acid and oxalic acid; (c) Hydroquinone

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