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以尿素、乙酸锌为前驱体,采用热聚合方法制备ZnO/g-C_3N_4复合光催化剂。通过X射线衍射、扫描电镜、红外光谱、紫外-可见光光谱及X射线电子能谱,对样品的晶体结构、形貌及光学性质进行表征。以紫外灯为光源,以酸性红(AR)为废水降解模型考察复合材料的光催化活性。结果表明:制得的复合光催化剂光催化性能要好于纯g-C_3N_4,且当ZnO∶g-C_3N_4=0.5∶1(摩尔比)时,光催化活性最高。复合后的光催化剂对反应底物有更强的吸附能力,能更有效地抑制电子-空穴的复合。进一步对AR的降解机理进行了探讨,发现超氧根自由基(O-·2)是使AR有效降解的活性物种。
ZnO / g-C_3N_4 composite photocatalyst was prepared by thermal polymerization using urea and zinc acetate as precursors. The crystal structure, morphology and optical properties of the samples were characterized by X-ray diffraction, scanning electron microscopy, infrared spectroscopy, ultraviolet-visible spectroscopy and X-ray photoelectron spectroscopy. The photocatalytic activity of the composites was investigated by using UV lamp as the light source and acid red (AR) as the wastewater degradation model. The results show that photocatalytic activity of the prepared composite photocatalyst is better than pure g-C_3N_4, and photocatalytic activity is the highest when ZnO: g-C_3N_4 = 0.5:1 (molar ratio). The composite photocatalyst has stronger adsorption ability to the reaction substrate, and can more effectively suppress electron-hole recombination. The mechanism of degradation of AR was further discussed. It was found that superoxide radical (O- · 2) is an active species that can effectively degrade AR.