氮化碳基复合催化剂的制备及其光催化性能研究

发布时间：2018-05-04 00:13

本文选题：氮化碳 + 钼酸铋　；参考：《常州大学》2017年硕士论文

【摘要】：近年来,光催化技术在有机污染物修复和清洁能源生产方面吸引了众多研究者的注意。类石墨相氮化碳(g-C_3N_4)因其高稳定性、廉价及特殊的电子能带结构等特点,被广泛应用于光催化领域。本论文为进一步拓展g-C_3N_4在环境污染方面的应用,制备出三种新型高效稳定的复合催化剂。主要研究内容及结果如下:(1)运用超声浸渍法制备了不同pH的Bi_2MoO_6/g-C_3N_4复合催化剂。采用XRD、FT-IR、TEM、BET、UV-vis等手段进行表征,并在可见光下通过降解罗丹明B(RhB)评价材料的光催性能。研究结果表明Bi_2MoO_6/g-C_3N_4能有效分离光生电子-空穴对从而表现出优于单体的光催化效果,且pH值不同也会导致催化剂具有不同的光催化效果。(2)通过热缩聚法制备了不同含硫量的石墨相氮化碳(g-CNS),并进一步合成硝基锌酞菁/含硫氮化碳(ZnTNPc/g-CNS)复合光催化剂。通过XRD、TEM、TG、XPS、EPR等手段表征催化剂的结构、形貌等。研究表明,S的加入使g-C_3N_4形成晶格缺陷促进光生电子-空穴对的分离,同时能够增大g-C_3N_4的比表面积。通过可见光条件下降解亚甲基蓝(MB)实验表明,ZnTNPc/g-CNS90呈现出最高的光催化活性且具有良好的稳定性。此外,还进一步探究了复合催化剂降解MB溶液过程中的可能性机理。在此研究基础上,进一步探究了不同酞菁取代基对光催化性能的影响。制备出锌酞菁/含硫氮化碳(ZnPc/g-CNS)、硝基锌酞菁/含硫氮化碳(ZnTNPc/g-CNS)、羧基锌酞菁/含硫氮化碳(ZnTCPc/g-CNS),并通过XRD、FT-IR、TEM、UV-vis等手段进行表征。在可见光下降解MB实验表明,取代基酞菁的催化活性优于无取代基酞菁,吸电子性强的基团能够优化酞菁的能带结构,更利于光催化反应的进行。(3)以SBA-15为模板制备介孔氮化碳(MCN),用原位生长法合成了SnS_2/MCN、CoS_2/MCN以及不同质量比的SnCoS_4/MCN复合催化剂。通过XRD、TEM、UV-vis、EDS、PL等对样品的结构、形貌、光学性质等进行表征。可见光下降解MB实验结果表明SnCoS_4/MCN(0.5)光催化性能最好。光催化机理研究发现,·OH、h+和·O2-是降解MB过程中活性物种。
[Abstract]:In recent years, photocatalytic technology has attracted the attention of many researchers in organic pollutant remediation and clean energy production. Graphite-like carbon nitride (C3N4) has been widely used in photocatalysis due to its high stability, low cost and special electronic band structure. In order to further expand the application of g-C_3N_4 in environmental pollution, three new high efficient and stable composite catalysts were prepared in this paper. The main contents and results are as follows: (1) Bi_2MoO_6/g-C_3N_4 composite catalysts with different pH were prepared by ultrasonic impregnation. The photocatalytic properties of the materials were characterized by XRDX FT-IRT-TEMT-BET-UV-vis, and the photocatalytic properties of the materials were evaluated by degradation of Rhodamine Bhh B under visible light. The results show that Bi_2MoO_6/g-C_3N_4 can effectively separate photogenerated electron-hole pairs and thus exhibit a better photocatalytic effect than monomers. Different pH values also lead to different photocatalytic effects. (2) Graphite phase nitrided carbon nitride with different sulfur content was prepared by thermal condensation method, and nitro zinc phthalocyanine / zinc nitride carbon nitride / ZnTNPc / g-CNS composite photocatalyst was further synthesized. The structure and morphology of the catalyst were characterized by means of XRDX, TGG, TGP, EPR and so on. The results show that the lattice defects of g-C_3N_4 can promote the separation of photogenerated electron-hole pairs and increase the specific surface area of g-C_3N_4. The degradation of methylene blue in visible light showed that ZnTNPc / g-CNS90 exhibited the highest photocatalytic activity and had good stability. In addition, the possible mechanism of the degradation of MB solution by the composite catalyst was further explored. On the basis of this study, the effects of different phthalocyanine substituents on photocatalytic properties were further investigated. Zinc phthalocyanine / sulfur-containing carbon nitride ZnPc / g-CNS, nitrozinc phthalocyanine / sulfide-containing carbon nitride ZnTNPc / g-CNS, carboxyl zinc phthalocyanine / sulfur-containing carbon nitride ZnTCPc / g-CNSEU were prepared and characterized by XRDFT-IRTEMUV-vis. The experimental results of MB degradation under visible light showed that the catalytic activity of substituted phthalocyanines was better than that of non-substituted phthalocyanines, and the band structure of phthalocyanines could be optimized by the groups with strong electron absorption. The mesoporous carbon nitride (MCNN) was prepared by using SBA-15 as a template. SNS _ 2 / MCNC _ (2 / C) / CoS-1 / MCN and SnCoS_4/MCN composite catalysts with different mass ratios were synthesized by in-situ growth method. The structure, morphology and optical properties of the samples were characterized by XRDX Tem Tem UV-visN EDSPL and so on. The experimental results of MB degradation under visible light show that SnCoS4 / MCN-0.5) has the best photocatalytic performance. The photocatalytic mechanism shows that OHH and O 2-are active species in the degradation of MB.
【学位授予单位】：常州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36

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