Morphology and dispersion of nanostructured manganese–cobalt spinel on various carbon supports: the effect on the oxygen reduction reaction in alkaline media

2018 ◽  
Vol 8 (2) ◽  
pp. 642-655 ◽  
Author(s):  
Aldona Kostuch ◽  
Joanna Gryboś ◽  
Paulina Indyka ◽  
Luigi Osmieri ◽  
Stefania Specchia ◽  
...  

Carbon carriers play a triple role in the ORR, determining nanoparticle dispersion, faceting, and reaction mechanism.

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 820
Author(s):  
Aldona Kostuch ◽  
Joanna Gryboś ◽  
Szymon Wierzbicki ◽  
Zbigniew Sojka ◽  
Krzysztof Kruczała

One of the practical efforts in the development of oxygen reduction reaction (ORR) catalysts applicable to fuel cells and metal-air batteries is focused on reducing the cost of the catalysts production. Herein, we have examined the ORR performance of cheap, non-noble metal based catalysts comprised of nanosized mixed Fe-Co spinels deposited on N,S-doped mesoporous carbon support (N,S-MPC). The effect of the chemical and phase composition of the active phase on the selectivity of catalysts in the ORR process in alkaline media was elucidated by changing the iron content. The synthesized materials were thoroughly characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectroscopy (RS). Detailed S/TEM/EDX and Raman analysis of the phase composition of the synthesized ORR catalysts revealed that the dominant mixed iron-cobalt spinel is accompanied by minor fractions of bare cobalt and highly dispersed spurious iron oxides (Fe2O3 and Fe3O4). The contribution of individual phases and their degree of agglomeration on the carbon support directly influence the selectivity of the obtained catalysts. It was found that the mixed iron-cobalt spinel single phase gives rise to significant improvement of the catalyst selectivity towards the desired 4e− reaction pathway, in comparison to the reference bare cobalt spinel, whereas spurious iron oxides play a negative role for the catalyst selectivity.


RSC Advances ◽  
2016 ◽  
Vol 6 (97) ◽  
pp. 94669-94681 ◽  
Author(s):  
Miguel A. Molina-García ◽  
Neil V. Rees

Four common catalyst carbon supports are quantitatively compared in an integrated study towards the oxygen reduction reaction in alkaline media.


2020 ◽  
Vol 9 (1) ◽  
pp. 843-852
Author(s):  
Hunan Jiang ◽  
Jinyang Li ◽  
Mengni Liang ◽  
Hanpeng Deng ◽  
Zuowan Zhou

AbstractAlthough Fe–N/C catalysts have received increasing attention in recent years for oxygen reduction reaction (ORR), it is still challenging to precisely control the active sites during the preparation. Herein, we report FexN@RGO catalysts with the size of 2–6 nm derived from the pyrolysis of graphene oxide and 1,1′-diacetylferrocene as C and Fe precursors under the NH3/Ar atmosphere as N source. The 1,1′-diacetylferrocene transforms to Fe3O4 at 600°C and transforms to Fe3N and Fe2N at 700°C and 800°C, respectively. The as-prepared FexN@RGO catalysts exhibited superior electrocatalytic activities in acidic and alkaline media compared with the commercial 10% Pt/C, in terms of electrochemical surface area, onset potential, half-wave potential, number of electrons transferred, kinetic current density, and exchange current density. In addition, the stability of FGN-8 also outperformed commercial 10% Pt/C after 10000 cycles, which demonstrates the as-prepared FexN@RGO as durable and active ORR catalysts in acidic media.


ChemSusChem ◽  
2014 ◽  
Vol 7 (12) ◽  
pp. 3356-3361 ◽  
Author(s):  
Zhiming Cui ◽  
Minghui Yang ◽  
Hao Chen ◽  
Mengtian Zhao ◽  
Francis J. DiSalvo

2019 ◽  
Vol 71 ◽  
pp. 234-241 ◽  
Author(s):  
Yun Sik Kang ◽  
Yoonhye Heo ◽  
Jae Young Jung ◽  
Yeonsun Sohn ◽  
Soo-Hyoung Lee ◽  
...  

RSC Advances ◽  
2015 ◽  
Vol 5 (2) ◽  
pp. 1571-1580 ◽  
Author(s):  
Dongyoon Shin ◽  
Beomgyun Jeong ◽  
Myounghoon Choun ◽  
Joey D. Ocon ◽  
Jaeyoung Lee

An optimal catalyst testing methodology that could allow precise benchmarking to obtain standardized ORR activity is put forward.


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