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Effects of cobalt precursor on pyrolyzed carbon-supported cobalt-polypyrrole as electrocatalyst toward oxygen reduction reaction.

Yuan X, Hu XX, Ding XL, Kong HC, Sha HD, Lin H, Wen W, Shen G, Guo Z, Ma ZF, Yang Y - Nanoscale Res Lett (2013)

Bottom Line: 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.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.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China. yuanxx519@163.com.

ABSTRACT
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.

No MeSH data available.


XRD patterns of Co-PPy-TsOH/C catalysts prepared from various cobalt precursors.
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Figure 4: XRD patterns of Co-PPy-TsOH/C catalysts prepared from various cobalt precursors.

Mentions: To understand the effects of cobalt precursor on electrochemical performance of the corresponding Co-PPy-TsOH/C catalysts, many physicochemical techniques have been employed in this work. Figure 4 presents XRD patterns of the Co-PPy-TsOH/C catalysts prepared from various precursors, the standard data for CoO and α-Co are also shown for comparison. Four apparent characteristic peaks can be clearly observed at 2θ of 24.5°, 44.2°, 51.5°, and 75.8° in all of the synthesized catalysts, which could be assigned to C(002), Co(111), Co(200), and Co(220) plane. This suggests that cobalt in the Co-PPy-TsOH/C catalysts exists mainly as metallic α-Co with face-centered cubic (fcc) structure. The Co(111) and Co(200) peaks become sharper and sharper with the order of cobalt acetate, cobalt nitrate, cobalt chloride and cobalt oxalate, implying a growth in the crystallite size of metallic cobalt. Generally, an average crystallite size, d, can be estimated with the Shcherrer equation [27,28]:


Effects of cobalt precursor on pyrolyzed carbon-supported cobalt-polypyrrole as electrocatalyst toward oxygen reduction reaction.

Yuan X, Hu XX, Ding XL, Kong HC, Sha HD, Lin H, Wen W, Shen G, Guo Z, Ma ZF, Yang Y - Nanoscale Res Lett (2013)

XRD patterns of Co-PPy-TsOH/C catalysts prepared from various cobalt precursors.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3842826&req=5

Figure 4: XRD patterns of Co-PPy-TsOH/C catalysts prepared from various cobalt precursors.
Mentions: To understand the effects of cobalt precursor on electrochemical performance of the corresponding Co-PPy-TsOH/C catalysts, many physicochemical techniques have been employed in this work. Figure 4 presents XRD patterns of the Co-PPy-TsOH/C catalysts prepared from various precursors, the standard data for CoO and α-Co are also shown for comparison. Four apparent characteristic peaks can be clearly observed at 2θ of 24.5°, 44.2°, 51.5°, and 75.8° in all of the synthesized catalysts, which could be assigned to C(002), Co(111), Co(200), and Co(220) plane. This suggests that cobalt in the Co-PPy-TsOH/C catalysts exists mainly as metallic α-Co with face-centered cubic (fcc) structure. The Co(111) and Co(200) peaks become sharper and sharper with the order of cobalt acetate, cobalt nitrate, cobalt chloride and cobalt oxalate, implying a growth in the crystallite size of metallic cobalt. Generally, an average crystallite size, d, can be estimated with the Shcherrer equation [27,28]:

Bottom Line: 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.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.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China. yuanxx519@163.com.

ABSTRACT
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.

No MeSH data available.