摘要
酞菁铁(FePc)是一种很有应用潜力的氧还原反应(ORR)非贵金属催化剂.FePc基催化材料的ORR活性通常在碱性条件下远远好于在酸性条件下的性能,但这种pH对其ORR活性影响的机理还不清楚.本文制备了全氟酞菁铁(FePcF_(16))与多壁碳纳米管(MWCNT)的复合材料FePcF_(16)/MWCNT,并在pH 1、4、7、10和13的电解液中评估了它的ORR活性.其中,在pH 13条件下,FePcF_(16)/MWCNT表现出优异的ORR性能,起始电位(E_(onset))和半波电位(E_(1/2))分别为1.011 V vs.RHE和0.875 V vs.RHE;随着pH的减小,ORR性能显著降低,pH 1时,E_(onset)和E_(1/2)分别降低为0.280 Vvs.RHE和0.185 V vs.RHE,表明FePcF_(16)/MWCNT的电化学活性在不同pH条件下具有显著差异.吸收光谱滴定实验和密度泛函理论计算证明FePcF_(16)在不同的pH条件下具有不同的电子结构,从而造成其ORR活性的pH依赖性.这项工作有利于提升对FePc基催化材料ORR电催化性能的认识,并为进一步设计相应的高性能催化材料提供了理论和实验基础.
Iron phthalocyanine(FePc)has emerged as a promising non-noble metal-based catalyst for the oxygen reduction reaction(ORR).FePc-based catalytic materials usually exhibit much better ORR activity under alkaline conditions than under acidic conditions.However,how pH affects the ORR activity is still unclear.Herein,iron hexadecafluorophthalocyanine(FePcF_(16))was combined with multi-walled carbon nanotubes(MWCNT)to generate a FePcF_(16)/MWCNT composite material.We evaluated the FePcF_(16)/MWCNT ORR activity in various solutions with pH=1,4,7,10,and 13.FePcF_(16)/MWCNT showed excellent ORR performance with an onset potential(E_(onset))of 1.011 V vs.RHE and a half-wave potential(E_(1/2))of 0.875 V vs.RHE at pH 13.Upon decreasing the pH,the ORR performance significantly degraded,with Eonset and E_(1/2) being reduced to 0.280 and 0.185 V vs.RHE at pH 1,respectively.According to the absorption spectrometric titration experiment and density functional theory(DFT)theoretical calculations,we demonstrated that the electronic structure of FePcF_(16) changes under different pH conditions,resulting in a pH-dependent ORR activity.This work will help to deeply understand the ORR properties of FePc-based catalytic materials and is in turn beneficial to promote the development of new catalysts with high ORR performance.
作者
郁宗华
詹晓宁
金昱丞
刘文苹
刘文博
姜蓉
齐冬冬
王康
姜建壮
Zonghua Yu;Xiaoning Zhan;Yucheng Jin;Wenping Liu;Wenbo Liu;Rong Jiang;Dongdong Qi;Kang Wang;Jianzhuang Jiang(Beijing Key Laboratory for Science and Application of Functional Molecular and Crystalline Materials,School of Chemistry and Biological Engineering,University of Science and Technology Beijing,Beijing 100083,China)
出处
《中国科学：化学》
CAS
CSCD
北大核心
2022年第8期1400-1407,共8页
SCIENTIA SINICA Chimica
基金
国家自然科学基金(编号:21631003,21671017,21871024)资助项目。
关键词
酞菁铁
多壁碳纳米管
pH依赖性
氧还原反应
催化机理
iron phthalocyanine
multi-walled carbon nanotubes
pH effect
oxygen reduction reaction
catalytic mechanism
