哈尔滨工业大学工学硕士学位论文
Abstract
The oxygen reduction reaction (ORR) plays an important role in the energy storage and conversion integretions such as metal air batteries and fuel cells. Noble metal catalysts have been intensively developed due to their high oxygen reduction activity. However, precious metal catalysts face the problems of scarce resources, high cost, weak resistance to methanol poisoning in catalytic reactions, and poor stability, which severely limit their application. In view of the above problems, non-noble metal Fe-N-C electrocatalyst and Cu-N-C catalysts and with high oxygen reduction activity and durability were designed to replace precious metal catalysts.
For the design of non-noble metal single-atom Fe-N-C catalysts, 2-methylimidazole (C4H6N2) and zinc nitrate (Zn(NO3)2·6H2O) was used to synthesis ZIF-8 through a simple liquid phase reaction, during which organic iron salt ferrocene (Fe(C5H5)2, Fc) as iron precursor dissolved in methanol was used iron source. The match of molecular size between ZIF-8 and Fc@ZIF-8 has a pore size of 3.4 ?, a cavity of 11 ?, and molecular size of ferrocene is 6.4 ?) make it possible to the fabrication of Fc@ZIF-8 structure, which can be ultilized as precursor for single-atom Fe-N-C catalyst. On the one hand, the precursor ZIF-8 has a porous structure, which turns to porous carbon skeleton with ultra high specific surface area after high temperature pyrolysis, which may help to improve the mass transfer of oxygen in the catalyst, and the explosion of active sites, enhancing oxygen reduction. On the other hand, the match of molecular size between ZIF-8 and Fc (ZIF-8 has a pore size of 3.4 ?, a cavity of 11 ?, and molecular size of ferrocene is 6.4 ?) makes it possible for a single ferrocene molecule to be trapped within the cavity of ZIF-8, making ferrocene molecules uniformly dispersed in the ZIF-8 bore. After pyrolysis at high temperature, the Fe was uniformly monodispersed in the porous carbon skeleton. The Fe-N-C catalyst was analyzed by X-ray absorption fine structure, and Fe was present in the Fe-N coordination form, proving that Fe is single-atom in the catalyst. that the catalyst was FeN X coordination is an active site. After the introduction of ferrocene, the oxygen reduction performance of the catalyst was significantly increased comparing with N-C catalyst derived from pure ZIF-8 with a half-wave potential of 0.75 V. The half-wave potential of single-atom Fe-N-C catalyst was 0.904 V, suggesting Fe-N coordination structure are highly active in ORR. Furthermore, single-atom Fe-N-C catalysts have significantly improved stability and resistance to methanol poisoning compared to commercial Pt/C catalysts.
For the design of the non-precious metal Cu-N-C catalyst, a simple liquid-phase mixing method was used. ZIF-8 was prepared using 2-methylimidazole (C4H6N2) and zinc nitrate
哈尔滨工业大学工学硕士学位论文
(Zn(NO3)2·6H2O) as raw materials. Taking ZIF-8 as the carrier and CuCl2 as the copper source, the Cu-ZIF-8 catalyst precursor was prepared by Cu2+ adsorption on the surface of ZIF-8 in a simple manner, and Cu-N-C catalyst was prepared by high-temperature pyrolysis. The structure of the Cu-N-C catalyst was verified by a series of physical characterizations as amorphous carbon materials. After the introduction of Cu, the oxygen reduction performance of the catalyst was significantly increased, as the half-wave potential of 0.76 V for N-C catalyst increased to 0.81 V for the Cu-N-C catalyst. The Cu-N-C catalyst has a significantly increased stability and resistance to methanol poisoning of commercial Pt/C catalysts and is also a valuable non-precious metal catalyst.
Keywords: Oxygen reduction, ZIF-8, Non-precious metal catalyst, single-atom Fe catalyst, Cu-N-C catalyst
哈尔滨工业大学工学硕士学位论文
目录
摘要 ..................................................................................................................... I Abstract ................................................................................................................. III
第1章绪论 (1)
1.1课题背景 (1)
1.2燃料电池的概述 (1)
1.2.1 燃料电池简介 (1)
1.2.2 燃料电池分类 (2)
1.2.3 燃料电池工作原理 (3)
1.2.4 燃料电池所遇到的问题 (4)
1.3贵金属铂基催化剂 (5)
1.4非贵金属催化剂 (7)
1.4.1 非金属碳基催化剂 (7)
1.4.2 过渡金属颗粒催化剂 (11)
1.4.3 非贵金属单原子催化剂 (14)
1.5本课题研究内容 (16)
第2章实验仪器及研究方法 (17)
2.1实验材料及实验设备 (17)
2.1.1 实验试剂与材料 (17)
2.1.2 实验仪器与设备 (17)
2.2催化剂的制备 (18)
2.2.1 Fe-N-C单原子催化剂的制备 (18)
2.2.2 Cu-N-C催化剂的制备 (19)
2.3催化剂物理表征 (19)
2.3.1 扫描电子显微镜表征（SEM） (19)
2.3.2 透射电子显微镜表征（TEM） (20)
2.3.3 X射线衍射光谱表征（XRD） (20)
2.3.4 X射线光电子能谱表征（XPS） (20)
2.3.5 红外光谱表征（FTIR） (20)
2.3.6 紫外光谱表征（UV-vis） (21)
哈尔滨工业大学工学硕士学位论文
2.3.7 拉曼光谱表征（Raman） (21)
2.3.8 N2吸脱附表征（BET） (21)
2.3.9 元素分析（ICP-OES） (21)
2.4催化剂电化学性能表征 (21)
2.4.1 三电极体系 (21)
2.4.2 旋转圆盘电极测试法（RDE） (22)
2.4.3 旋转环盘电极测试法（RRDE） (23)
第3章Fe-N-C单原子催化剂的制备与表征 (24)
3.1引言 (24)
3.2Fe-N-C单原子催化剂的表征 (25)
3.2.1 催化剂的形貌表征 (25)
3.2.2 催化剂前躯体的结构表征 (27)
3.2.3 催化剂的结构表征 (28)
3.2.4 催化剂的电化学性能表征 (32)
3.3本章小结 (36)
第4章Cu-N-C催化剂的制备与表征 (38)
4.1引言 (38)
4.2Cu-N-C催化剂的表征 (39)
4.2.1 Cu-N-C催化剂的形貌表征 (39)
4.2.2 Cu-N-C催化剂的结构表征 (42)
4.2.3 Cu-N-C催化剂的电化学性能表征 (46)
4.3本章小结 (50)
结论 (52)
参考文献 (54)
攻读硕士学位期间发表的学术论文及其它成果 (61)
哈尔滨工业大学学位论文原创性声明和使用权限 (62)
致谢 (63)