Effects of cobalt precursor on pyrolyzed carbon-supported cobalt-polypyrrole as electrocatalyst toward oxygen reduction reaction
1 Department of Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
2 School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, China
3 Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academic of Science, Shanghai 201204, China
4 Institute of Micro-Nano Science and Technology, Shanghai Jiao Tong University, Shanghai 200240, China
5 State Key Laboratory of Physical Chemistry of Solid Surface & Department of Chemistry, Xiamen University, Xiamen 361005, China
Nanoscale Research Letters 2013, 8:478 doi:10.1186/1556-276X-8-478Published: 14 November 2013
A series of non-precious metal electrocatalysts, namely pyrolyzed carbon-supported cobalt-polypyrrole, Co-PPy-TsOH/C, are synthesized with various cobalt precursors, including cobalt acetate, cobalt nitrate, cobalt oxalate, and cobalt chloride. The catalytic performance towards oxygen reduction reaction (ORR) is comparatively investigated with electrochemical techniques of cyclic voltammogram, rotating disk electrode and rotating ring-disk electrode. The results are analyzed and discussed employing physiochemical techniques of X-ray diffraction, transmission electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, inductively coupled plasma, elemental analysis, and extended X-ray absorption fine structure. It shows that the cobalt precursor plays an essential role on the synthesis process as well as microstructure and performance of the Co-PPy-TsOH/C catalysts towards ORR. Among the studied Co-PPy-TsOH/C catalysts, that prepared with cobalt acetate exhibits the best ORR performance. The crystallite/particle size of cobalt and its distribution as well as the graphitization degree of carbon in the catalyst greatly affects the catalytic performance of Co-PPy-TsOH/C towards ORR. Metallic cobalt is the main component in the active site in Co-PPy-TsOH/C for catalyzing ORR, but some other elements such as nitrogen are probably involved, too.