新型金属有机框架复合纳米材料的合成及其在光催化及电催化的应用
发布时间：2018-12-12 06:50
【摘要】：针对金属有机框架在各种领域中的应用,对其光催化和电催化性能进行研究。从光催化中的光催化氧化一氧化氮,到电催化中的燃料电池阴极氧还原反应,就大气环境问题,以及世界能源问题展开研究。本文主要采用微波辅助合成的方法,合成了两种新型的金属有机框架催化剂。其中光催化剂在可见光照射下,考察了其在流动相中对一氧化氮的光催化氧化去除活性。电催化剂在常温环境下,考察了其在碱性体系中对氧气的电催化氧还原反应的活性和稳定性,以及在甲醇体系中的稳定性。期望通过这些研究,为环境、能源、化工、机动车等提供高效的催化剂和先进技术。(1)微波合成掺金的金属有机骨架(Ti)及其可见光光催化氧化NO的研究采用微波辅助合成技术,成功制备出了一种具有可见光光催化氧化去除一氧化氮活性的新型金属有机框架NH_2-MIL-125(Ti)。通过浸渍还原法均匀负载金纳米颗粒,获得Au@NH_2-MIL-125(Ti),负载金纳米颗粒后能显著提高金属有机框架NH_2-MIL-125(Ti)催化剂的光催化活性且具有优良的稳定性。金纳米颗粒有利于提高光的捕获能力,同时还能促进光生电子的快速传导,从而降低光生电子与空穴的复合,提高光催化活性。(2)新型CNT/ZIF基多孔碳复合纳米材料(Co-N-CNT)的合成及其在氧还原反应中的应用选用非贵金属电催化剂,以钴作为金属活性位点,为了增加导电性,以碳纳米管作为连接,用以促进电子传递。最终选用ZIF-67作为牺牲模版。用微波合成法制备CNT/ZIF-67,在氩气下进行高温热处理,制备出的Co-N-CNT-700催化剂显示较好的电催化氧还原反应(ORR)活性;制备的催化剂Co-N-CNT-700与商用20%Pt/C催化剂进行电催化ORR活性、耐甲醇性及稳定性对比,其活性均优于商用20%Pt/C催化剂。通过研制开发新型催化剂和优化催化材料,着重解决目前光催化氧化一氧化氮所存在的由于光利用率低、光生电子-空穴复合率高等因素造成的低效率,结合相关表征和动力学测试,揭示了光催化氧化一氧化氮的机理和构效关系。以及目前电催化氧还原反应中存在的催化剂造价高、制备过程复杂、催化剂易中毒等因素造成的电催化剂利用率低的问题,结合相关表征以及电化学测试,解释了电催化氧还原反应的机理。
[Abstract]:The photocatalytic and electrocatalytic properties of organometallic frames in various fields were studied. From photocatalytic oxidation of nitric oxide in photocatalysis to cathodic oxygen reduction of fuel cells in electrocatalysis, atmospheric environmental problems and world energy problems have been studied. In this paper, two new organometallic framework catalysts were synthesized by microwave-assisted synthesis. The photocatalytic oxidation of nitric oxide in mobile phase was investigated by photocatalyst under visible light irradiation. The activity and stability of electrocatalytic oxygen reduction reaction in alkaline system and the stability in methanol system were investigated under normal temperature. Looking forward to these studies for the environment, energy, chemicals, (1) Microwave-assisted synthesis of gold-doped organometallic (Ti) and its visible light catalytic oxidation of NO are studied by microwave assisted synthesis. A novel metal-organic framework (NH_2-MIL-125 (Ti).) with visible photocatalytic oxidation activity for removal of nitric oxide was successfully prepared. Au@NH_2-MIL-125 (Ti), was obtained by uniformly loading gold nanoparticles by impregnation reduction method. The photocatalytic activity of organometallic framework NH_2-MIL-125 (Ti) catalyst can be improved by loading gold nanoparticles and has good stability. Gold nanoparticles can improve the ability to capture light and accelerate the fast conduction of photogenerated electrons, thus reducing the combination of photogenerated electrons and holes. (2) Synthesis of new CNT/ZIF based porous carbon nanocomposite (Co-N-CNT) and its application in oxygen reduction reaction using non-noble metal electrocatalyst with cobalt as the active site. To increase electrical conductivity, carbon nanotubes are used as connections to facilitate electron transfer. Finally, ZIF-67 is chosen as the sacrificial template. CNT/ZIF-67, was prepared by microwave synthesis under high temperature heat treatment in argon. The prepared Co-N-CNT-700 catalyst showed good (ORR) activity in oxygen reduction reaction. Compared with the commercial 20%Pt/C catalyst, the prepared Co-N-CNT-700 catalyst was superior to the commercial 20%Pt/C catalyst in the electrocatalytic ORR activity, methanol tolerance and stability. By developing new catalysts and optimizing catalytic materials, the low efficiency caused by low photocatalytic oxidation of nitric oxide (no) and high photoelectron / hole recombination rate is solved. The mechanism and structure-activity relationship of photocatalytic oxidation of nitric oxide were revealed by correlation characterization and kinetic tests. And the problems of low utilization rate of electrocatalyst caused by high cost, complex preparation process and easy poisoning of catalyst in the current electrocatalytic oxygen reduction reaction, combined with related characterization and electrochemical test. The mechanism of electrocatalytic oxygen reduction is explained.
【学位授予单位】：上海师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36
本文编号：2374124
[Abstract]:The photocatalytic and electrocatalytic properties of organometallic frames in various fields were studied. From photocatalytic oxidation of nitric oxide in photocatalysis to cathodic oxygen reduction of fuel cells in electrocatalysis, atmospheric environmental problems and world energy problems have been studied. In this paper, two new organometallic framework catalysts were synthesized by microwave-assisted synthesis. The photocatalytic oxidation of nitric oxide in mobile phase was investigated by photocatalyst under visible light irradiation. The activity and stability of electrocatalytic oxygen reduction reaction in alkaline system and the stability in methanol system were investigated under normal temperature. Looking forward to these studies for the environment, energy, chemicals, (1) Microwave-assisted synthesis of gold-doped organometallic (Ti) and its visible light catalytic oxidation of NO are studied by microwave assisted synthesis. A novel metal-organic framework (NH_2-MIL-125 (Ti).) with visible photocatalytic oxidation activity for removal of nitric oxide was successfully prepared. Au@NH_2-MIL-125 (Ti), was obtained by uniformly loading gold nanoparticles by impregnation reduction method. The photocatalytic activity of organometallic framework NH_2-MIL-125 (Ti) catalyst can be improved by loading gold nanoparticles and has good stability. Gold nanoparticles can improve the ability to capture light and accelerate the fast conduction of photogenerated electrons, thus reducing the combination of photogenerated electrons and holes. (2) Synthesis of new CNT/ZIF based porous carbon nanocomposite (Co-N-CNT) and its application in oxygen reduction reaction using non-noble metal electrocatalyst with cobalt as the active site. To increase electrical conductivity, carbon nanotubes are used as connections to facilitate electron transfer. Finally, ZIF-67 is chosen as the sacrificial template. CNT/ZIF-67, was prepared by microwave synthesis under high temperature heat treatment in argon. The prepared Co-N-CNT-700 catalyst showed good (ORR) activity in oxygen reduction reaction. Compared with the commercial 20%Pt/C catalyst, the prepared Co-N-CNT-700 catalyst was superior to the commercial 20%Pt/C catalyst in the electrocatalytic ORR activity, methanol tolerance and stability. By developing new catalysts and optimizing catalytic materials, the low efficiency caused by low photocatalytic oxidation of nitric oxide (no) and high photoelectron / hole recombination rate is solved. The mechanism and structure-activity relationship of photocatalytic oxidation of nitric oxide were revealed by correlation characterization and kinetic tests. And the problems of low utilization rate of electrocatalyst caused by high cost, complex preparation process and easy poisoning of catalyst in the current electrocatalytic oxygen reduction reaction, combined with related characterization and electrochemical test. The mechanism of electrocatalytic oxygen reduction is explained.
【学位授予单位】：上海师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36
【参考文献】
相关期刊论文 前1条
1 Xuemei Wang;Jianmin Chen;Tiantao Cheng;Renyi Zhang;Xinming Wang;;Particle number concentration, size distribution and chemical composition during haze and photochemical smog episodes in Shanghai[J];Journal of Environmental Sciences;2014年09期
，本文编号：2374124
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