Hydrothermal/Solvothermal Synthesis and Photocatalytic Performance of ZnS Microspheres

doi:10.15541/jim20150508

Abstract

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

CLC Number:

O643

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.

Figures/Tables 7

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

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

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

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

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

Fig. 6 Phenol degradation cycling tests of ZnS

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

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