直接硼氢化物燃料电池核壳结构阳极催化剂制备及性能研究
发布时间：2019-06-26 14:03
【摘要】：燃料电池是一种能将燃料中的化学能直接转变成电能的新型电源装置。以硼氢化钠(NaBH4)碱性水溶液为燃料的直接硼氢化物燃料电池(DBFC)使用的燃料性质稳定,易于储存和运输,电池理论电压与比能量高。理论上,BH4-的电氧化过程为8 e-转移反应,但由于BH4-中的H-组分具有1S2的特殊结构,易失去电子,性质极不稳定。所以,BH4-在进行直接电氧化反应的同时还会发生水解反应,这无疑会降低燃料利用率。因此,研究BH4-在不同金属电极材料上的电化学氧化反应行为及放电特性,开发高效多功能复合电极催化剂,具有十分重要的意义。首先,本文以连续两步化学还原法制备了不同比例的碳载核壳结构Cu-Pd (Cu@Pd/C)纳米粒子催化剂。并利用XRD、TEM、EDS等对纳米粒子进行物理表征；采用CV、CP、CA和电池测试等技术进行电化学分析。结果表明：所制备的Cu@Pd/C粒径为9m左右的近似球形的核壳结构纳米粒子,但存在一定程度的团聚现象。Cu@Pd/C均有比单金属Pd/C更大的电化学活性面积(ECSA),并且展示出较好的电催化性能。不同Cu、Pd比例的纳米粒子表现出不同的催化性能,当Cu1@Pd1/C用作DBHFC阳极催化剂时,在20℃时获得的功率密度达到40mWcm-2。其次,本文以反相微乳液——连续两步化学还原法制备了不同比例的Ni@Au/C催化剂。通过物理和电化学方法表征得出以下结果：Ni@Au/C纳米粒子粒径约为10nm的核壳结构,具有较好的分散性。随着Au壳层厚度的逐渐减薄,催化性能表现为先增大后减小的趋势。计算出Au/C、 Ni1@Au2/C、Ni1@Au1/C和Ni2@Au1/C的ECSA分别为161.0 cm2 mg-1,348.1 cm2mg-1,815.7cm2mg-1和402.4 cm2 mg-1, Ni1@Au1/C有最大的ECSA并且也有较好的稳定性,在CV实验中基于al氧化峰转移的电子数为6.6。在20℃时,以Ni1@Au1/C为阳极催化剂,Pt网(1 cm×1 cm)为阴极电极组装成DBHFC,获得的功率密度为74mWcm-2,是相同条件下Au/C催化剂的4倍。本论文所制备的核壳结构催化剂对BH；均表现出比单金属催化剂更好的电催化氧化性能,这是由核壳结构特殊的电子效应和几何效应引起的。在一定厚度的壳层时,核心金属对壳层金属的d电子轨道产生适宜的诱导效应,使得BH4-在壳层金属表面的吸附力适中,比较有利于BH4-的吸附和反应产物的脱附。本文制备的Cu1@Pd1/C或Ni1@Au1/C纳米粒子的催化性能较好,这与其微观结构有关,两种催化剂壳层均排列了3～4层Pd原子或Au原子,同时,Cu1@Pd1/C和Ni1@Au1/C均具有的较大的ECSA。
[Abstract]:Fuel cell is a new type of power supply device which can directly convert the chemical energy in fuel into electric energy. The direct borohydrate fuel cell (DBFC) with sodium borohydrate (NaBH4) alkaline aqueous solution as fuel has stable fuel properties, easy storage and transportation, and high theoretical voltage and specific energy of the cell. In theory, the electrooxidation process of BH4- is 8 e-transfer reaction, but because the H-component in BH4- has the special structure of 1S2, it is easy to lose electrons and the properties are very unstable. Therefore, the hydrolysis of BH4- will occur at the same time of direct electrooxidation, which will undoubtedly reduce the fuel utilization rate. Therefore, it is of great significance to study the electrochemical oxidation behavior and discharge characteristics of BH4- on different metal electrode materials and to develop efficient multifunctional composite electrode catalysts. Firstly, different proportion of carbon-supported core-shell Cu-Pd (Cu@Pd/C) nanoparticles catalysts were prepared by continuous two-step chemical reduction method. The nanoparticles were physically characterized by XRD,TEM,EDS and electrochemical analysis was carried out by CV,CP,CA and battery testing. The results show that the prepared Cu@Pd/C nanoparticles with approximately spherical core-shell structure with a particle size of about 9m have a certain degree of agglomeration. Copper @ Pd/C has a larger electrochemical active area (ECSA), than monometallic Pd/C and shows better electrocatalytic performance. The catalytic performance of nanoparticles with different Cu,Pd ratios is different. When Cu1@Pd1/C is used as anode catalyst for DBHFC, the power density can reach 40 MW / cm at 20 鈩，
本文编号：2506239
[Abstract]:Fuel cell is a new type of power supply device which can directly convert the chemical energy in fuel into electric energy. The direct borohydrate fuel cell (DBFC) with sodium borohydrate (NaBH4) alkaline aqueous solution as fuel has stable fuel properties, easy storage and transportation, and high theoretical voltage and specific energy of the cell. In theory, the electrooxidation process of BH4- is 8 e-transfer reaction, but because the H-component in BH4- has the special structure of 1S2, it is easy to lose electrons and the properties are very unstable. Therefore, the hydrolysis of BH4- will occur at the same time of direct electrooxidation, which will undoubtedly reduce the fuel utilization rate. Therefore, it is of great significance to study the electrochemical oxidation behavior and discharge characteristics of BH4- on different metal electrode materials and to develop efficient multifunctional composite electrode catalysts. Firstly, different proportion of carbon-supported core-shell Cu-Pd (Cu@Pd/C) nanoparticles catalysts were prepared by continuous two-step chemical reduction method. The nanoparticles were physically characterized by XRD,TEM,EDS and electrochemical analysis was carried out by CV,CP,CA and battery testing. The results show that the prepared Cu@Pd/C nanoparticles with approximately spherical core-shell structure with a particle size of about 9m have a certain degree of agglomeration. Copper @ Pd/C has a larger electrochemical active area (ECSA), than monometallic Pd/C and shows better electrocatalytic performance. The catalytic performance of nanoparticles with different Cu,Pd ratios is different. When Cu1@Pd1/C is used as anode catalyst for DBHFC, the power density can reach 40 MW / cm at 20 鈩，
本文编号：2506239
本文链接：https://www.wllwen.com/kejilunwen/dianlilw/2506239.html
教材专著
