花簇状g-C3N4/Bi2MoO6微球的制备及光催化降解模拟染料废水

Bio-assisted fabrication of flower-like g-C3N4/Bi2MoO6 microspheres and mechanism of visible-light driven photocatalytic degradation of simulated dye wastewater

摘要:

以酵母为生物模板，通过水热-牺牲模板法制备得到了花簇状g-C3N4/Bi2MoO6复合微球，利用XRD、SEM、TEM、FT-IR、DRS、光电流响应以及氮气吸附-脱附等手段对样品的晶体结构、微观形貌、光吸收和比表面积等性能进行表征，并对样品可见光催化降解亚甲基蓝（MB）模拟染料废水的性能和机理进行探讨。实验结果表明：水热-牺牲模板法可实现g-C3N4与Bi2MoO6在生物模板表面的成功复合，样品分散性良好，微球直径约为8μm，表面呈花簇状，比表面积达11.6007m2/g。在可见光下复合微球对亚甲基蓝模拟染料废水表现出较高的光催化降解活性，当催化剂添加量为1g/L，可见光照射120min后，初始浓度为15mg/L的亚甲基蓝废水降解率高达96%以上。机理分析证实花簇状复合微米球表面g-C3N4与Bi2MoO6形成的Z型异质结有效降低了电子-空穴的复合率，显著提升了对模拟染料废水的可见光催化性能。

Abstract:

Using yeasts as biological templates, flower-like g-C3N4/Bi2MoO6 microspheres were prepared via hydrothermal-template sacrifices method. The crystal phase, microstructure, light absorption and specific surface area of the as-prepared sample was characterized with various techniques including XRD, SEM, TEM, FT-IR, DRS, photocurrent response and nitrogen adsorption-desorption. We also examined the visible-light driven photocatalytic performance of g-C3N4/Bi2MoO6 composite microspheres for methylene blue (MB) simulated dye wastewater. The experimental results showed that g-C3N4/Bi2MoO6 composite was successfully synthesized on the surface of yeast templates through hydrothermal-template sacrifices method, and the as-obtained microspheres with diameter at about 8 microns were of good dispersity. The surface of the g-C3N4/Bi2MoO6 microspheres were composed of flower-like nano-clusters, and the specific surface area of composite sample reached 11.6007 m2/g. The results of photocatalytic experiments verified remarkable visible-light driven photocatalytic performance of flower-like g-C3N4/Bi2MoO6 microspheres for methylene blue simulated dye wastewater. The degradation efficiency for the MB simulated dye wastewater at initial concentration of 15 mg/L was beyond 96%, when the as-prepared photocatalyst was added at dosage of 1 g/L and the mixture was irradiated under visible light for 120 min. Mechanism analysis demonstrated that the formation of Z-type heterojunction between g-C3N4 and Bi2MoO6 on the flower-like surface of bio-templated microspheres reduced the recombination rate of electronic-hole remarkably and enhanced the visible-light driven photocatalytic efficiency for simulated dye wastewater significantly.