Boosting oxygen reduction activity of spinel CoFe2O4 by strong interaction with hierarchical nitrogen-doped carbon nanocages  

作　　者：Hao Fan Lijun Yang Yu Wang Xiali Zhang Qingsong Wu Renchao Che Meng Liu Qiang Wu Xizhang Wang Zheng Hu 

机构地区：[1]Key Laboratory of Mesoscopic Chemistry of Ministry of Education and Jiangsu Provincial Lab for Nanotechnology, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China [2]Department of Materials Science and Advanced Materials Laboratory, Fudan University, Shanghai 200438, China

出　　处：《Science Bulletin》2017年第20期1365-1372,共8页科学通报（英文版）

基　　金：supported by the National Natural Science Foundation of China (21473089, 51232003, 21373108, 21573107, and 51571110);the National Basic Research Program of China (2013CB932902);Changzhou Technology Support Program (CE20130032);Priority Academic Program Development of Jiangsu Higher Education Institutions;Fundamental Research Funds for the Central Universities

摘　　要：The unique hierarchical nitrogen-doped carbon nanocages(h NCNC) are used as a new support to homogeneously immobilize spinel Co Fe_2O_4 nanoparticles by a facile solvothermal method. The so-constructed hierarchical Co Fe_2O_4/h NCNC catalyst exhibits a high oxygen reduction activity with an onset potential of0.966 V and half-wave potential of 0.819 V versus reversible hydrogen electrode, far superior to the corresponding 0.846 and 0.742 V for its counterpart of Co Fe_2O_4/h CNC with undoped hierarchical carbon nanocages(h CNC) as the support, which locates at the top level for spinel-based catalysts to date.Consequently, the Co Fe_2O_4/h NCNC displays the superior performance to the Co Fe_2O_4/h CNC, when used as the cathode catalysts in the home-made Al-air batteries. X-ray photoelectron spectroscopy characterizations reveal the more charge transfer from Co Fe_2O_4 to h NCNC than to h CNC, indicating the stronger interaction between Co Fe_2O_4 and h NCNC due to the nitrogen participation. The enhanced interaction and hierarchical morphology favor the high dispersion and modification of electronic states for the active species as well as the mass transport during the oxygen reduction process, which plays a significant role in boosting the electrocatalytic performances. In addition, we noticed the high sensitivity of O 1 s spectrum to the particle size and chemical environment for spinel oxides, which is used as an indicator to understand the evolution of ORR activities for all the Co Fe_2O_4-related contrast catalysts. Accordingly,the well-defined structure-performance relationship is demonstrated by the combination of experimental characterizations with theoretical calculations. This study provides a promising strategy to develop efficient, inexpensive and durable oxygen reduction electrocatalysts by tuning the interaction between spinel metal oxides and the carbon-based supports.The unique hierarchical nitrogen-doped carbon nanocages （hNCNC） are used as a new support to homo- geneously immobilize spinel CoFe2O4 nanoparticles by a facile solvothermal method. The so-constructed hierarchical CoFe2O4/hNCNC catalyst exhibits a high oxygen reduction activity with an onset potential of 0.966 V and half-wave potential of 0.819 V versus reversible hydrogen electrode, far superior to the corresponding 0.846 and 0.742 V for its counterpart of CoFe2O4/hCNC with undoped hierarchical carbon nanocages （hCNC） as the support, which locates at the top level for spinel-based catalysts to date. Consequently, the CoFe2O4/hNCNC displays the superior performance to the CoFe2O4/hCNC, when used as the cathode catalysts in the home-made Al-air batteries. X-ray photoelectron spectroscopy characterizations reveal the more charge transfer from CoFe2O4 to hNCNC than to hCNC, indicating the stronger interaction between CoFe2O4 and hNCNC due to the nitrogen participation. The enhanced interaction and hierarchical morphology favor the high dispersion and modification of electronic states for the active species as well as the mass transport during the oxygen reduction process, which plays a significant role in boosting the electrocatalytic performances. In addition, we noticed the high sensitivity of 0 ls spectrum to the particle size and chemical environment for spinel oxides, which is used as an indicator to understand the evolution of ORR activities for all the CoFe2O4-related contrast catalysts. Accordingly, the well-defined structure-performance relationship is demonstrated by the combination of experimental characterizations with theoretical calculations. This study provides a promising strategy to develop efficient, inexpensive and durable oxygen reduction electrocatalysts by tuning the interaction between spinel metal oxides and the carbon-based supprts.

关 键 词：Oxygen reduction electrocatalyst Spinel cobalt ferrite oxide Hierarchical nitrogen-doped carbon NANOCAGES Strong interaction Structure-performance relationship Al-air battery 

分 类 号：O643.36[理学—物理化学]