【作者】 荆俊杰；

【导师】 谢吉民；

【作者基本信息】 江苏大学 ， 清洁能源与环境保护， 2014， 博士

【摘要】 当前资源短缺问题日渐突出,资源消耗已逼近环境承载极限。如何减少有限资源的浪费,提高其利用率,已成为人们关注的热点。目前广泛使用的催化剂以性能优良的金、铂、钯、银等贵金属为主,但它们储量有限价格高昂,且由于其催化活性组分在纳米颗粒的表面,核中大部分的贵金属会被浪费掉。引入Fe、Ni、Cu等便宜的金属到核部分是一种有效节约贵金属催化剂生产成本的方法。运用纳米制备技术,以铜替代贵金属,制备出结构新颖、性能优越的复合材料,在增强催化活性的同时,有效降低催化剂的成本,提高贵金属资源的利用率,具有重要的理论意义和应用价值。铜纳米材料的控制合成已取得了很大的进展,但是,探索铜纳米材料生成过程中的影响因素,设计简便易行的合成路线,制备出形貌新颖的纳米材料并拓展其应用仍然具有重要的意义。本论文旨在通过合理的技术路线,合成形貌结构新颖的铜纳米粒子和铜基复合纳米材料,并研究其在催化方面的性能。采用XRD、SEM-EDS、TEM、DRS、 UV-vis、ICP、EA等测试手段对合成的催化剂的结构、形貌、光电性能及催化性能进行研究。本文的具体研究内容如下：1.采用溶剂热的方法,控制反应的条件,使用CuI和VCNa分别制得了梭形、绒球形和花形的铜微纳米粒子。研究了微纳米铜的生长过程,并简单探讨了微纳米铜的生长机理。用以上制备的铜微纳米材料对苯乙炔和苄基叠氮进行链接反应时的催化作用进行了相应研究。比较了各种形貌微纳米铜的催化活性,其中微米花状的铜催化性能最好。2.应用反相微乳液的方法制备了大小可控的纳米铜粒子。考查了还原剂硼氢化钠的使用量对制备铜纳米粒子的影响。研究了各种铜盐作为前驱体制备纳米铜的情况,结果表明氯化铜和醋酸铜能制备得到纯纳米铜,而硝酸铜则不能制备得到纯纳米铜。通过控制反相微乳液体系中水相和乳化剂的比例,成功制备出了形貌均一,粒径大小可控的铜纳米粒子。3.通过反相微乳液的方法,制备出结构新颖的Cu@Ag和Cu@Ag/RGO(还原石墨烯)核壳结构的纳米复合材料。采用XRD、TEM、EDS、ICP、EA等测试手段对制备得到的纳米材料的微观结构及其组成进行了相应的表征。对于Cu@Ag纳米粒子,由各表征得到的结果综合分析,其确为铜核银壳的核壳结构纳米粒子。对于Cu@Ag/RGO纳米粒子,分析表明,Cu@Ag核壳纳米粒子能较密集的均匀分布于RGO表层之上,且其结构与单一未经负载的核壳纳米粒子无差异。对所得到的纳米材料进行加氢催化研究,结果表明,所制备出的Cu@Ag和Cu@Ag/RGO纳米核壳材料的催化性能均十分优良,并且Cu@Ag/RGO优于Cu@Ag。4.通过反相微乳液的方法,制备出结构新颖的以铜为核贵金属金、铂、钯等材料为壳的核壳结构纳米材料。采用XRD、TEM、EDS、ICP等测试手段对制备得到的纳米材料的微观结构及其组成进行了相应的表征。对于各纳米粒子,由各表征得到的结果综合分析,可以得出结论,所制备得到的纳米材料确为以铜为核而外壳分别是由金、铂、钯所构成的核壳结构纳米粒子。并且通过控制贵金属盐加入量的方法,制备出组成可控的核壳材料。对所得到的核壳材料进行加氢催化研究,结果表明,所制备出的各核壳纳米材料其催化性能均远好于单纯的铜和贵金属材料。5.通过反相微乳液的方法,制备出结构新颖的RGO负载铜为核贵金属金、铂、钯等材料为壳的核壳结构的复合纳米材料。采用XRD、TEM、EDS、ICP、EA等测试手段对制备所得到的复合纳米材料的微观结构及其组成进行了相应的表征。对于各复合纳米粒子,由各表征得到的结果综合分析,可以得出结论,已经成功制备得到RGO负载Cu@(Au、Pt、Pd)纳米粒子的复合纳米材料。各种复合纳米粒子能较密集的均匀分布于RGO表层之上,并且其结构与单一未经负载的核壳纳米粒子无差异。对所得到的纳米材料进行加氢催化研究,结果表明,所制备出的RGO负载Cu@(Au、Pt、Pd)纳米核壳材料,其催化性能较相应的未经负载RGO的核壳纳米粒子有了明显的改善,也均远好于相应的单纯的RGO负载铜、金、铂、钯的材料。更多还原

【Abstract】 Currently, the issue of resource shortage has been increasingly prominent and the resource consumption has been approximating the limit of environmental carrying capacity. How to reduce the waste of the limited resources and elevate their utilization rate has been a focus of people’s attention. The catalysts widely used currently are dominated by such precious metals with excellent properties as gold, platinum, palladium, silver etc. but they have limited reserves and high prices. In addition, most of the precious metals in the nucleus will be wasted due to the fact that their catalytic activity components are on the surface of the nanoparticles. Introduction of such cheap metals as Fe, Ni, Cu etc. is an effective method to save the production cost of precious metal catalysts. The resource utilization rate can be elevated and the consumption of precious metals can be reduced by using the nano preparation technique and substituting the copper for precious metals. Thus, preparation of composite materials with a novel structure and excellent properties is significant theoretically and practically. Much progress has been made in the controlled synthesis of copper nanomaterials but it is still significant to explore the influencing factors during generation of cooper nanomaterials, design a simple and feasible synthetic route, prepare nanomaterials with a novel morphology, and expand their applications.The paper aims to synthesize copper crystals and copper-based composite nanomaterials with a novel morphological structure by appropriate means and study their properties in catalysis. A study was conducted for the structure, morphology, photoelectric properties, and catalytic properties of the synthesized catalyst tested by such test methods as XRD, SEM-EDS, TEM, DRS, UV-vis, ICP, EA. The results are as follows:1. A micro-nano copper crystals with a novel morphological structure was prepared by using Cul and VCNa under controlled reaction conditions with the solvothermal method. There has been no relevant report on shuttle-shaped, pompons-shaped, and flower-shaped products. Research was conducted for the growth process of the micro-nano copper and simple discussion was made for the growth mechanism of the micro-nano copper. An appropriate study was conducted for the catalysis during the ligation reaction between phenylacetylene and azidomethyl using the copper micro-nano material prepared above. Comparisons of catalytic activity were made among various micro-nano copper and the copper micron flower had the best catalytic performance.2. Nano-copper particles with a controllable size were prepared by the method of reversed microemulsion. An investigation was made to examine the effect of the dosage of the reductant of the sodium borohydride on preparation of the copper nano particles. Research on preparation of nano-copper was made with various copper salts as the precursors and the results showed that pure nano-copper could be prepared by using copper chloride and copper acetate while pure ano-copper could not be prepared with copper nitrate. Copper nano particles with a uniform morphology and controllable size were successfully prepared by controlling the proportion of the water phase and emulgator in the reverse microemulsion systems.3. Nano-composite materials of Cu@Ag and Cu@Ag/RGO core-shell structure were prepared with the method of reversed microemulsion. Appropriate characterization was performed for the microstructure and composition of the nanomaterial prepared by such testing methods as XRD, TEM, EDS, UV-vis, ICP, EA etc. Based on a comprehensive analysis of the results from various characterizations, the Cu@Ag nano particles were really ones of core-shell structure (copper core and silver shell). The analysis showed that Cu@Ag core-shell nano particles were able to densely distribute on the surface layer of RGO. And, their structure was the same as that of the unloaded core-shell nano particles. A hydrogenation catalysis study was conducted for the nanomaterials obtained. The result indicated that catalytic performance of the Cu@Ag and Cu@Ag/RGO nano core-shell materials prepared was very excellent. And the catalytic performance of Cu@Ag/RGO was better than that of Cu@Ag.4. Nanomaterial with a novel structure was prepared by use of reversed microemulsion. It is core-shell structure with copper as the core and noble metals such as gold, platinum, palladium as the shell. Appropriate characterization was performed by XRD, TEM, EDS, UV-vis, ICP for the for the microstructure and composition of the nanomaterials prepared. Based on a comprehensive analysis of the results from characterization of the various nano particles, it could be concluded that the nanomaterials prepared were really nano particles of core-shell structure with copper as the core and gold, platinum, and palladium as the shell. In addition, core-shell materials with controllable components were prepared by controlling the amount of precious metal salt added. A hydrogenation catalysis study was conducted for the core-shell material obtained. The results showed that the catalytic performance of all core-shell nanomaterials prepared was far more higher than that of pure copper and precious metal materials.5. Nanomaterial with a novel structure was prepared with the method of reversed-phase microemulsion. It is of core-shell structure with RGO-loading copper as the core and the precious metals of gold, platinum, palladium etc. as the shell. Appropriate characterization was performed for the microstructure and composition of the composite nanomaterial prepared by such testing methods as XRD, TEM, EDS, UV-vis, ICP, EA etc. Based on a comprehensive analysis of the results from characterization of various composite nano particles, it could be concluded that the composite nanomaterial with RGO-loading Cu@(Au, Pt, and Pd) nano particles had been successfully prepared. Various composite nano particles were able to densely distribute on the surface layer of RGO. And, their structure was the same as that of the unloaded core-shell nano particles. A hydrogenation catalysis study was conducted for the nanomaterials obtained. The result showed that the catalytic performance of the RGO-loading Cu@(Au, Pt, and Pd) nanomaterials prepared significantly improved compared with the core-shell nano particles unloaded with RGO. And the catalytic performance was much better than appropriate pure RGO-loading copper, gold, platinum and palladium materials.更多还原