原位氟掺杂碳纳米管阵列的微结构调控制备过程及其氧还原反应特性研究

The slow cathode oxygen reduction reaction in fuel cells is one of the key bottleneck factors restricting the industrialization process. Based on the study of low-cost, high-performance oxygen reduction electrode materials for fuel cells, this project puts forward in situ fluorine-doped carbon nanotube array as a new metal-free electrode material for oxygen reduction. Controllable preparation is adopted by using water-assisted chemical vapor deposition method. The micro-structure and electrocatalytic properties of these catalysts are investigated systematically. . This project will study the influence of growth temperature, growth time, moisture content and growth matrix on controllable preparing fluorine-doped carbon nanotube arrays. It will regulate the doping amounts and forms of fluorine in carbon nanotube arrays and investigate the micro-structure of carbon nanotube array,such as purity,defects and surface state by changing the type and amount of fluorine-containing precursors. It will study the catalytic activity, stability and selectivity both in acidic and alkaline environments. It will definite the correlation of controllable preparation,micro-structure and catalytic activity in the fluorine-doped carbon nanotube arrays, illuminate the catalytic mechanism both in acid and alkaline electrolytes, analysis the effect of fluorine and carbon atoms on catalyzing oxygen reduction reaction. The implementation of this project will promote the development and application of the energy storage system which is based on the oxygen reduction reaction.

燃料电池缓慢的阴极氧还原反应是制约其产业化进程的瓶颈之一。本项目以低成本高性能氧还原电极材料为研究对象，提出原位氟掺杂碳纳米管阵列的新型非金属氧还原催化剂，探索水分辅助化学气相沉积法可控制备过程特性，并对其微结构及电催化特性进行系统研究。. 本项目将重点考察反应温度、反应时间、水分含量等参数及生长基体对氟掺杂碳纳米管阵列结构的影响，通过改变含氟前驱体种类和用量来调控碳纳米管阵列中氟的掺入量和掺杂方式，研究氟掺杂碳纳米管阵列的缺陷位和表面状态等微观结构，分别在酸性和碱性环境中，研究氟掺杂碳纳米管阵列的氧还原催化活性、稳定性和选择性，揭示氟掺杂碳纳米管阵列的可控制备过程、微观结构及氧还原催化性能三者之间的“制-构-效”关系，阐明氟掺杂碳纳米管阵列在酸性和碱性环境中催化机理和氟碳原子间催化氧还原的相互作用。本项目的实施将促进以氧还原反应为基础的燃料电池和相关储能电池的技术发展。

碳纳米材料是一类新型催化剂材料、载体材料，在燃料电池等催化领域具有广阔的应用前景，碳纳米材料具有较高的比表面积和表面催化活性，具有绿色可循环，成本较低等优点，是理想的电极催化剂材料。本项目采用碳纳米管(CNTs），导电炭黑（BP2000）为载体材料，通过氟化铵（NH4F）与BP2000分别在700℃、800℃、900℃、1000℃进行热处理制备催化剂，利用旋转环盘电极考察出HT900性能较好，平均电子转移数n为3.92，在30000s循环后电流衰减率为11%，具有较高的氧还原效率和稳定性，并利用透射电镜、扫描电镜、X射线衍射、X光电子能谱等技术对材料的形貌、结构、组成进行了表征；以改性BP2000为载体研究F与金属原子Fe/Co共掺杂制备FBP-Co、FBP-Fe，利用循环伏安法考察最佳热处理工艺参数为900℃；以经过HF处理的三聚氰胺（MF）与BP2000混合制备催化剂NFC，研究表明1000℃处理后性能最优，氧还原电位为-0.2Vvs.SCE，经过20000s计时电流法测试，电流衰减率为17%，并具有良好的抗甲醇性能；以三聚氰胺在HF和H3PO4, H2SO4的溶液中进行改性，与BP2000、过渡金属Fe/Co混合分别制备催化剂MPFS-BP、10Co-MPF-BP、10Fe-MF-BP，其中10Fe-MF-BP-800氧还原电位为-0.1099Vvs.SCE，平均电子转移数为3.94；其中10Co-MPF-BP-800性能较好；而MPFS-BP在1000℃时具有较好的氧还原性能。通过对于催化剂制备工艺及性能的研究，达到制备、结构、性能相对应的规律，总结出最佳的制备工艺参数。在该课题的资助下。项目负责人已以第一作者和通讯作者在在Journal of The Electrochemical Society，International Journal of Hydrogen Energy，ECS Electrochemistry Letters，有色金属材料与工程等期刊发表论文6篇。