全氟酞菁铁电催化氧还原反应活性的pH依赖性  

The pH-dependent catalytic activity of the oxygen reduction reaction of iron hexadecafluorophthalocyanine

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)

机构地区：[1]北京科技大学化学与生物工程学院,功能分子与晶态材料科学与应用北京市重点实验室,北京100083

出　　处：《中国科学：化学》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。

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.

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 

分 类 号：O643.36[理学—物理化学]