多巴胺为前驱体过渡金属与N共同掺杂的碳纳米管催化剂ORR性能研究

Study Electrocatalytic Performance for Oxygen Reduction Reaction of Dopamine Derived Transition Metal-Nitrogen Codoped Carbon Nanotube

采用多巴胺的自氧化聚合在多壁碳纳米管表面进行聚合沉积修饰,经热处理可得到氮掺杂的碳纳米管催化剂,通过调整沉积次数可控制表面聚多巴胺C-N膜的厚度,从而调控N的掺杂量.研究沉积次数对多壁碳纳米管催化剂表面形貌、化学组成及原子结合形态的影响,并考察N掺杂的多壁碳纳米管催化剂的氧还原反应活性.在此基础上,用多巴胺配合Mn、Fe离子进行共同聚合沉积,热处理后得到Mn(Fe)、N共同掺杂的多壁碳纳米管催化剂,对催化剂进行了多种测试和电化学表征.循环伏安和线性扫描的电化学表征表明,N掺杂可有效提高催化剂的氧还原反应(ORR)活性,C-N膜的厚度会影响催化剂性能,Mn(Fe)-N@MWCNTs催化剂的氧还原活性高于只有N掺杂的催化剂,两种催化剂氧还原反应均为4电子反应路径,可直接将氧气还原成H_2O,且F e-N@MWCNTs催化剂表现出较好的抗甲醇能力.SEM照片可以看到聚多巴胺在碳纳米管表面形成C-N膜;R aman分析表明聚多巴胺沉积后提高了催化剂表面的无序性,缺陷增多;XPS表征显示过渡金属的掺杂改变了CN_x的结合状态.

In this paper, polydopamine was deposited polymerization of dopamine, and then N-doped carbon on the surface of multi-walled carbon nanotube through self- nanotube was obtained pyrolysis. The influence of deposition time on the surface morphology, chemical composition and atomic bonding mode was studied, and the catalytic ac- tivity of N-doped carbon nanotube for oxygen reduction reaction was investigated. On this basis, dopamine comple- xing Mn or Fe ion codeposited on the carbon nanotube, and Mn （Fe）, Ndoped carbon nanotube was obtained by pyrolysis. Cyclic vohammograms and linear sweep voltammetry showed that doped N can effectively improve the ca- talyst activity for oxygen reduction reaction, and the catalytic activity was further improved after Fe, N doped. The oxygen reduction reaction on all the catalyst exhibited 4 electron reaction pathway. And Fe-N@ MWCNTs contains good methanol-tolerant property. SEM photos showed obviously that polydopamine nanofilm was formed on the sur- face of carbon nanotube ; Raman spectra indicated that the disorder and defects of catalyst increased, compared with carbon nanotube. XPS result showed that the combination of the transition metal changed the CNx bonding mode.