摘要
以炭纸为载体,通过原位水热法合成了一系列炭纸负载的尖晶石结构铁氧体MFe_(2)O_(4)微球催化剂(M^(2+)=Fe^(2+),Co^(2+),Ni^(2+)和Zn^(2+)),研究了铁氧体中M^(2+)的种类和外磁场特性对催化剂OER性能的影响.结果表明:炭纸负载的NiFe_(2)O_(4)(NFO-Ms/C)具有优异的OER性能,在10 mA∙cm^(-2)时的过电位为409 mV、Tafel斜率为78.9 mV∙dec^(-1)、电化学活性表面积为1.6 mF∙cm^(-2),这主要是因为NiFe_(2)O_(4)中存在较多的高价态M^(3+)和较低的导电率、丰富的氧空位,有利于加快OER反应的速率.稳定性测试表明,60 h后NFO-Ms/C的过电位仅升高5%左右,这主要是由于催化剂不断由Ni^(2+)转变为高活性的N^(3+),保持着较好的催化活性.外界交变磁场能提高NFO-Ms/C的OER性能,当交变磁场强度为4.320 mT,NFO-Ms/C的过电位由455 mV下降到了315 mV(10 mA∙cm^(-2)),降低了30.8%,这是由于交变磁场生成的感生电场使电极表面活性物质OH-增多提升了电极电势,磁热效应提供额外能量加速电荷传输.
A series of carbon paper-supported spinel structure ferrite MFe_(2)O_(4)microsphere catalysts(M^(2+)=Fe^(2+),Co^(2+),Ni^(2+),and Zn^(2+))were synthesized via an in-situ hydrothermal method using carbon paper as the substrate.The influence of the type of M^(2+)in the ferrite and the characteristics of an external magnetic field on the catalyst’s oxygen evolution reaction(OER)performance was investigated.Results indicate that carbon paper-supported NiFe_(2)O_(4)(NFO-Ms/C)exhibits excellent OER performance,with an overpotential of 409 mV at 10 mA·cm^(-2),a Tafel slope of 78.9 mV·dec^(-1),and an electrochemically active surface area of 1.6 mF·cm^(-2).This superior performance is primarily attributed to the abundance of higher-valent M^(3+)ions in NiFe_(2)O_(4),coupled with its lower conductivity and abundant oxygen vacancies,which collectively facilitate the OER process.Stability tests reveal that the overpotential of the catalyst increases by only approximately 5%after 60 hours,mainly due to surface reconstruction of the catalyst.An external alternating magnetic field can enhance the OER performance of NFOMs/C.When the intensity of the alternating magnetic field is 4.320 mT,the overpotential of NFO-Ms/C decreases from 455 mV to 315 mV at 10 mA·cm^(-2),representing a 30.8%reduction.This is due to the induced electric field generated by the alternating magnetic field,which increases the concentration of active surface species OH-on the electrode,thereby enhancing the electrode potential,and the magnetocaloric effect provides additional energy to accelerate charge transfer.
作者
高朋召
景帅齐
王垣力
胡天隆
孟悦欣
李长泉
周锋
刘小磐
肖汉宁
GAO Pengzhao;JING Shuaiqi;WANG Yuanli;HU Tianlong;MENG Yuexin;LI Changquan;ZHOU Feng;LIU Xiaopan;XIAO Hanning(College of Materials Science and Engineering,Hunan University,Changsha 410082,China)
出处
《湖南大学学报(自然科学版)》
北大核心
2025年第8期193-205,共13页
Journal of Hunan University:Natural Sciences
关键词
析氧反应
原位负载
铁氧体
外场增效
oxygen evolution reaction
in-situ loading
ferrite
external field enhancement effect
