scholarly journals Polyacrylamide Microspheres-Derived Fe3C@N-doped Carbon Nanospheres as Efficient Catalyst for Oxygen Reduction Reaction

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 767 ◽  
Author(s):  
Ming Chen ◽  
Yu Jiang ◽  
Ping Mei ◽  
Yan Zhang ◽  
Xianfeng Zheng ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Electrocatalytic Activity ◽  
Active Sites ◽  
Reduction Reaction ◽  
Limiting Current ◽  
Alkaline Solutions ◽  
Carbon Nanospheres ◽  
Hydrogen Electrode ◽  
Efficient Catalyst

High-performance non-precious metal catalysts exhibit high electrocatalytic activity for the oxygen-reduction reaction (ORR), which is indispensable for facilitating the development of multifarious renewable energy systems. In this work; N-doped carbon-encapsulated Fe3C nanosphere ORR catalysts were prepared through simple carbonization of iron precursors loaded with polyacrylamide microspheres. The effect of iron precursors loading on the electrocatalytic activity for ORR was investigated in detail. The electrochemical measurements revealed that the N-doped carbon-encapsulated Fe3C nanospheres exhibited outstanding electrocatalytic activity for ORR in alkaline solutions. The optimized catalyst possessed more positive onset potential (0.94 V vs. reversible hydrogen electrode (RHE)), higher diffusion limiting current (5.78 mA cm−2), better selectivity (the transferred electron number n > 3.98 at 0.19 V vs. RHE) and higher durability towards ORR than a commercial Pt/C catalyst. The efficient electrocatalytic performance towards ORR can be attributed to the synergistic effect between N-doped carbon and Fe3C as catalytic active sites; and the excellent stability results from the core-shell structure of the catalysts.

ZIF-67-derived N-doped double layer carbon cage as efficient catalyst for oxygen reduction reaction

2021 ◽  
Author(s):  
Wenwen Zhang ◽  
Ximeng Zhao ◽  
Weixing Niu ◽  
Hang Yu ◽  
Tongtao Wan ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Double Layer ◽  
Active Sites ◽  
Specific Capacity ◽  
Hollow Structure ◽  
Protective Layer ◽  
Reduction Reaction ◽  
Efficient Catalyst ◽  
Carbon Cage

Abstract The slow kinetic of oxygen reduction reaction (ORR) hampers the practical application of energy conversion devices, such as fuel cells, metal-air batteries. Here, an efficient ORR electrocatalyst consists of Co, Ni co-decorated nitrogen-doped double shell hollow carbon cage (Ni-Co@NHC) was fabricated by pyrolyzing Ni-doped polydopamine wrapped ZIF-67. During the preparation, polydopamine served as a protective layer can effectively prevented the aggregation of Co and Ni nanoparticles during the pyrolysis process, and at the same time forming a carbon layer to grow a double layer carbon cage. This unique hollow structure endows the catalyst with a high specific surface area as well as more exposed active sites. Also benefited from the synergistic effect between Ni and Co nanoparticles, the Ni-Co@NHC catalyst lead to an outstanding ORR performance of half-wave potential (E1/2, 0.862 V), outperforms that of commercial Pt/C catalyst. Additionally, when Ni-Co@NHC was used in the cathode for the zinc-air battery, the cell exhibits high power density (108 mW cm-2) and high specific capacity (806 mAh g-1) at 20 mA cm-2 outperforming Pt/C. This work offers a promising design strategy for the development of high-performance ORR electrocatalysts.

scholarly journals Highly effective Fe-N-C electrocatalysts toward oxygen reduction reaction originated from 2,6-diaminopyridine

2021 ◽  
Author(s):  
Weixiang Yang ◽  
Shuihua Tang ◽  
Qiankuan Huang ◽  
Qian Zhang ◽  
Zhen Tang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Photoelectron Spectroscopy ◽  
Active Sites ◽  
Cost Effective ◽  
Reduction Reaction ◽  
Limiting Current ◽  
X Ray ◽  
Onset Potential

Abstract Fe-N-C electrocatalysts have been intensively studied due to their extraordinary catalytic activity toward oxygen reduction reaction (ORR). Here we prepare a Fe-N-C electrocatalyst through cost-effective and nontoxic precursors of 2,6-diaminopyridine (DAP) and FeCl3, where iron ions react with DAP to formed Fe-Nx species first, followed by polymerization and pyrolysis. X-ray diffraction patterns display no obvious Fe2O3 peaks observed in the catalyst as the nominal content of iron addition is less than 10 wt%. X-ray photoelectron spectroscopy spectra indicate that the catalyst has rich pyridinic nitrogen, graphitic nitrogen and Fe-Nx species, which are considered as active sites for ORR. Therefore the catalyst demonstrates an excellent catalytic activity with an onset potential of about 0.96 V, half-wave potential of about 0.84 V, and a limiting current density of 5.8 mA cm-2, better than commercial Pt/C catalyst in an alkaline medium. Furthermore its stability is also much more excellent than that of Pt/C. This work provides a strategy to synthesize universal M-N-C catalysts.

scholarly journals Hydrothermal Carbon/Carbon Nanotube Composites as Electrocatalysts for the Oxygen Reduction Reaction

2020 ◽  
Vol 4 (1) ◽  
pp. 20 ◽  
Author(s):  
Rafael G. Morais ◽  
Natalia Rey-Raap ◽  
Rui S. Costa ◽  
Clara Pereira ◽  
Alexandra Guedes ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Ball Milling ◽  
Active Sites ◽  
Chemical Reactivity ◽  
Carbon Composite ◽  
Reduction Reaction ◽  
Limiting Current

The oxygen reduction reaction is an essential reaction in several energy conversion devices such as fuel cells and batteries. So far, the best performance is obtained by using platinum-based electrocatalysts, which make the devices really expensive, and thus, new and more affordable materials should be designed. Biomass-derived carbons were prepared by hydrothermal carbonization in the presence of carbon nanotubes with different oxygen surface functionalities to evaluate their effect on the final properties. Additionally, nitrogen functional groups were also introduced by ball milling the carbon composite together with melamine. The oxygen groups on the surface of the carbon nanotubes favor their dispersion into the precursor mixture and the formation of a more homogenous carbon structure with higher mechanical strength. This type of structure partially avoids the crushing of the nanotubes and the carbon spheres during the ball milling, resulting in a carbon composite with enhanced electrical conductivity. Undoped and N-doped composites were used as electrocatalysts for the oxygen reduction reaction. The onset potential increases by 20% due to the incorporation of carbon nanotubes (CNTs) and nitrogen, which increases the number of active sites and improves the chemical reactivity, while the limiting current density increases by 47% due to the higher electrical conductivity.

Monoatomic-thick graphitic carbon nitride dots on graphene sheets as an efficient catalyst in the oxygen reduction reaction

Nanoscale ◽  
2015 ◽  
Vol 7 (7) ◽  
pp. 3035-3042 ◽  
Author(s):  
Xiaopeng Wang ◽  
Lixia Wang ◽  
Fei Zhao ◽  
Chuangang Hu ◽  
Yang Zhao ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Electrocatalytic Activity ◽  
Carbon Nitride ◽  
Reduction Reaction ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
Graphene Sheets ◽  
Efficient Catalyst

Monoatomic-thick graphitic carbon nitride dots on graphene sheets rival the electrocatalytic activity of the commercial Pt/C catalyst in the oxygen reduction reaction.

scholarly journals Degradation and regeneration of Fe-Nx active sites for oxygen reduction reaction: the role of surface oxidation, Fe demetallation and local carbon microporosity

2021 ◽  
Author(s):  
Dongsheng Xia ◽  
Chenchen Yu ◽  
Yinghao Zhao ◽  
Yinping Wei ◽  
Haiyan Wu ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Active Sites ◽  
Proton Exchange Membrane ◽  
Degradation Mechanism ◽  
Surface Oxidation ◽  
Reduction Reaction ◽  
Proton Exchange ◽  
Exchange Membrane

The severe degradation of Fe-N-C electrocatalysts during long-term oxygen reduction reaction (ORR) has become a major obstacle for application in proton-exchange membrane fuel cells. Understanding the degradation mechanism and regeneration...

Sign in / Sign up

Export Citation Format

Share Document