应用于氧气析出反应的四氧化三钴基催化材料的制备与性能研究

发布时间：2018-04-30 04:15

本文选题：Co_3O_4 + 铁掺杂　；参考：《北京化工大学》2015年硕士论文

【摘要】：氧气析出反应在燃料电池和电解水制氢等能源领域中具有广泛的应用。目前,贵金属及贵金属氧化物(如Ru、Ir、RuO2、IrO2等)是氧气析出反应常用的催化剂,然而贵金属价格昂贵、储量稀少,限制了其进一步应用。因此,研究开发低成本、高性能的氧气析出反应催化剂具有重要意义。本论文致力于研究低成本、高性能的非贵金属一一四氧化三钴(Co3O4)基氧气析出反应催化剂,通过形貌调控、碳载体负载以及金属掺杂进一步提高Co3O4的比表面积和电导率,从而有效提高催化剂的电催化活性和稳定性。首先,采用水热法制备了尖晶石结构的Co3O4,通过调控碱浓度、反应温度、醇水比等条件,实现了对催化剂微观形貌的有效调控,合成Co3O4纳米颗粒、纳米棒、纳米块、纳米线、纳米片等催化剂。物性表征和电化学测试表明,催化剂的微观形貌对其电催化活性影响较大,其中粒径为4-7 nm的Co3O4纳米颗粒催化剂具有最高的催化活性,在电流密度为10 mA·cm-2条件下,电位为0.690V (vs.SCE)。其次,为提高Co3O4催化剂的比表面积和电导率,采用高温石墨化炭黑(GCB)为载体,通过油浴搅拌法制备了Co3O4/GCB催化剂,通过调控热处理温度、醇水比以及负载量等条件,提高了Co3O4/GCB催化剂的氧气析出催化活性。研究表明,所制备的催化剂Co3O4纳米颗粒在GCB载体上分散较均匀,粒径约为5 nnl,具有较大的比表面积和较低的电阻率。电化学测试表明,Co3O4/GCB催化剂具有优于Co3O4催化剂的氧气析出催化活性和电化学稳定性,在10 mA·cm-2条件下,电位减小为0.670V,稳定性测试中,在一定电位下,Co304催化剂和Co3O4/GCB催化剂电流密度的衰减分别为10%和20%。最后,采用铁对Co3O4/GCB催化剂进行掺杂,制备了FexCoyO4/GCB催化剂,和Co3O4催化剂相比电阻率减小,进一步提高了氧气析出催化活性。在电流密度为10 mA·cm-2条件下,FexCoyO4/GCB催化剂的电位为0.637 V,较未掺杂的Co3O4/GCB催化剂减小了33 mV,具有优异的氧气析出催化活性。稳定性测试表明,经过1000圈电化学扫描,FexCoyO4/GCB催化剂几乎未发生衰减,表现出优异的电化学稳定性。Co3O4基催化材料因其优异的氧气析出反应催化能力,在新能源技术的发展中表现出良好的潜力。
[Abstract]:Oxygen precipitation reaction has been widely used in fuel cell and electrolytic water for hydrogen production. At present, precious metals and precious metal oxides (such as Ruziru, Ruo _ 2o _ 2o _ 2 and so on) are common catalysts for oxygen precipitation reaction. However, precious metals are expensive and have few reserves, which limit their further application. Therefore, it is of great significance to develop low-cost and high-performance catalysts for oxygen precipitation reaction. In this paper, the low cost and high performance catalysts for oxygen precipitation of non-noble metal cobalt trioxide (Co _ 3O _ 4) were studied. The surface area and conductivity of Co3O4 were further improved by means of morphology control, carbon carrier loading and metal doping. Thus, the electrocatalytic activity and stability of the catalyst are improved effectively. Firstly, Co _ 3O _ 4 with spinel structure was prepared by hydrothermal method. By controlling the concentration of alkali, reaction temperature and ratio of alcohol to water, the Co3O4 nanoparticles, nanorods, nanomaterials and nanowires were synthesized. Nanoparticles, etc. The results of physical characterization and electrochemical test showed that the micromorphology of the catalyst had a great influence on the electrocatalytic activity, and the Co3O4 nanoparticles with a particle size of 4-7 nm had the highest catalytic activity. The potential was 0.690 V / v 路SCEN at the current density of 10 Ma / cm-2. Secondly, in order to improve the specific surface area and conductivity of Co3O4 catalyst, Co3O4/GCB catalyst was prepared by oil bath stirring method using high temperature graphitization carbon black as the carrier. The temperature of heat treatment, the ratio of alcohol to water and the loading amount were adjusted. The oxygen precipitation activity of Co3O4/GCB catalyst was improved. The results show that the prepared catalyst Co3O4 nanoparticles are uniformly dispersed on the GCB support with a particle size of about 5 nnl.The catalyst has a large specific surface area and low resistivity. Electrochemical measurements showed that the catalytic activity of CO _ 3O _ 4 / GCB catalyst was superior to that of Co3O4 catalyst in oxygen precipitation and electrochemical stability. At 10 Ma cm-2, the potential decreased to 0.670 V, and in the stability test, the oxygen precipitation activity of Co _ 3O _ 4 / GCB catalyst was better than that of Co3O4 catalyst. The decay of current density of Co304 catalyst and Co3O4/GCB catalyst is 10% and 20% respectively at certain potential. Finally, Co3O4/GCB catalyst was doped with iron to prepare FexCoyO4/GCB catalyst. Compared with Co3O4 catalyst, the resistivity of FexCoyO4/GCB catalyst was reduced, which further improved the catalytic activity of oxygen precipitation. At the current density of 10 Ma cm-2, the potential of FexCoyO4 / GCB catalyst is 0.637 V, which is 33 MV lower than that of undoped Co3O4/GCB catalyst, and has excellent catalytic activity for oxygen precipitation. The stability test showed that the catalyst of FexCoyO4 / GCB had almost no decay after 1000 cycles of electrochemical scanning, and showed excellent electrochemical stability. Co3O4-based catalyst showed excellent catalytic ability for oxygen precipitation reaction. Show good potential in the development of new energy technology.
【学位授予单位】：北京化工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ138.12;O643.36

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