CTAB调控溶剂热制备C3N4及光催化性能的研究
本文以二聚氰胺和三聚氰氯为原料，采用低温溶剂热法合成出氮化碳纳米微球，并以CTAB为模板剂和结构导向剂对原料聚合过程进行调控。对产物进行X-射线衍射（XRD）、扫描电子显微镜（SEM）、X-射线光电子能谱（XPS）和紫外可见漫反射（UV-Vis DRS）表征，对其晶相、形貌、元素结构以及光吸收性质进行了详细的分析。以光催化分解有机染料为手段对其光催化性能进行评价。
研究结果表明，以CTAB对溶剂热合成CN的过程进行调控，不改变纳米微球的形貌形成，但过量CTAB的加入会引起微球之间的团聚。CTAB参与分子聚合，引起产物中的碳含量增大，导致聚合度下降，共轭结构单元的有序度受到抑制。含碳量的增加促进了对光的吸收能力，但半导体能带不发生变化。适量CTAB对CN的调控能够加速对有机染料(甲基橙和玫瑰红B)的光催化分解速率。机理研究表明，此类催化剂对有机染料的分解过程中起主要作用的基团是超氧自由基。
毕业论文关键词：石墨相氮化碳；CTAB；溶剂热；光催化降解
Abstract what is a direction of research on renewable clean resources is that using the photocatalytic technology to convert solar energy into the energy that could be directly used by people in order to solve problems about environmental pollution。As a metal free polymer semiconductor,g-C3N4 has unique electronic structures and excellent chemical stability,which has aroused the attention of many scientists。It is widely used in photocatalytic purification of environmental pollutants,however,its lower catalytic efficiency makes further modification and optimization become the key point of the research。The effective regulation of morphology by using the solvent thermal method is one of the main research directions in the modification of carbon nitride。
The paper used dicyandiamide and cyanuric chloride as raw materials,carbon nitride nanoparticles were synthesized by a solvothermal method at low temperature, and using CTAB as template and structure directing agent of raw materials polymerization process control。The product is characterized by XRD、XPS、SEM and UV-Vis DRS in order to analyse its crystal phase, morphology, structure and optical absorption properties of the crystal minutely。Furthermore,we would like to evaluate its photocatalytic property by means of photocatalytic decomposition of organic dyes。
The results show that CTAB can regulate the process of CN what was synthesized by using the solvent thermal method,and the morphology of the nanoparticles could not be changed, but the addition of excess CTAB could cause the aggregation of microspheres。 When CTAB is involved in molecular polymerization, which leads to the increase of the carbon content in the product and the decrease of the degree of polymerization,it can also result in that the order of the conjugated structure units is suppressed。The increase of carbon content promotes the absorption ability of the light, but the semiconductor energy band is not changed。A balanced amount of CTAB on the regulation of CN can accelerate the photocatalytic decomposition rate of organic dye (methyl orange and Rhodamine B)。Mechanism study shows that the group what plays main role of this kind of catalyst on the decomposition of organic dyes was superoxide radical。
Keywords：g-C3N4; CTAB; solvothermal; photocatalytic degradation