scholarly journals Oxygen reduction reaction by electrochemically reduced graphene oxide

2014 ◽  
Vol 173 ◽  
pp. 415-428 ◽  
Author(s):  
Santosh Kumar Bikkarolla ◽  
Peter Cumpson ◽  
Paul Joseph ◽  
Pagona Papakonstantinou

We show that a partially reduced graphene oxide electrocatalyst, synthesized by electrochemical reduction of graphene oxide (GO), displays significantly enhanced catalytic activity towards the oxygen reduction reaction (ORR) in alkaline solutions compared to the starting GO. The electrochemical partial reduction of GO was confirmed by X-ray diffraction and X-ray photoelectron spectroscopy. Electrochemical impedance spectroscopy (EIS) verified the enhanced electron transfer ability of the electrochemically reduced graphene oxide (ErGO) compared to GO. The resultant ErGO electrode showed enhanced capacitance and an ORR onset potential of −0.11 V vs. Ag/AgCl, similar to that of a nitrogen doped reduced graphene oxide (NrGO) electrode produced by a hydrothermal process. However the ErGO exhibited considerably lower electron transfer numbers (2.0–3.3 at a potential range of −0.4 V to −1.0 V) indicating that although both catalysts operate under combined 4e− and 2e− ORR processes, ErGO follows a more predominant 2e− pathway. The ORR process in ErGO has been linked to the presence of quinone functional groups, which favour the 2e− ORR pathway.

NANO ◽  
2016 ◽  
Vol 11 (11) ◽  
pp. 1650126 ◽  
Author(s):  
GuanHua Jin ◽  
Suqin Liu ◽  
Yaomin Li ◽  
Yang Guo ◽  
Zhiying Ding

Development of efficient electrocatalysts for the oxygen reduction reaction (ORR) remains a key issue for the commercialization of metal-air batteries. In this study, the novel structured Co3O4 nanoparticles-modified [Formula: see text]-MnO2 nanorods supported on reduced graphene oxide (Co3O4-MnO2/rGO) were synthesized with varying amounts of [Formula: see text]-MnO2 via a facile two-step hydrothermal method. The relationship between the physical properties and the electrochemical results was investigated using X-ray diffraction spectrum, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, cyclic voltammograms, electrochemical impedance spectroscopy and rotating disk electrode. The as-prepared Co3O4–MnO2 nanohybrid exhibits enhanced catalytic activity for ORR under alkaline condition compared with MnO2/rGO and Co3O4/rGO. Furthermore, it mainly favors a direct 4e-reaction pathway for ORR, which is attributed to the well-designed structure, the synergistic effect between Co3O4 and [Formula: see text]-MnO2, and the covalent coupling between the Co3O4-MnO2 and reduced graphene oxide. The role of Co3O4 in Co3O4–MnO2 hybrid for catalyzing ORR also has been illustrated by varying the mass ratio of Co3O4 and MnO2, which reveals that the Co3O4–MnO2 with the ratio of 1:1 has better catalytic activity.


NANO ◽  
2018 ◽  
Vol 13 (05) ◽  
pp. 1850047 ◽  
Author(s):  
Yang Lv ◽  
Xianbao Wang ◽  
Tao Mei ◽  
Jinhua Li ◽  
Jianying Wang

Cobalt phosphide (CoP) has aroused extensive research interest in a field of electrochemical application due to its excellent catalytic activities. CoP and its compounds have been widely reported using in hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). However, few reports about CoP as electrocatalysts for oxygen reduction reaction (ORR) were presented. In this work, we prepare reduced graphene-oxide(rGO)-loaded CoP (rGO@CoP) as an electrocatalyst for ORR through in situ hydrothermal treatment. The rGO@CoP as ORR catalyst exhibits excellent activities where its onset potential has a positive increase of 129[Formula: see text]mV, and the ORR potential achieves an increase of 330[Formula: see text]mV at a current density of 1.0[Formula: see text]mA[Formula: see text]cm[Formula: see text] compared with that of pure CoP. The current density is also significantly improved with an increase of 0.51[Formula: see text]mA[Formula: see text]cm[Formula: see text] at [Formula: see text]350[Formula: see text]mV, and the Tafel slope has a decrease of 19[Formula: see text]mV dec[Formula: see text]. Further tests show that the electron transfer number of rGO@CoP is 3.66, which is larger than 2.19 of pure CoP, indicating that it is dominated by a four-electron transfer pathway. Moreover, its stability (remained 98.6% current after working 6000[Formula: see text]s) and methanol tolerance are outstanding. These results show that rGO@CoP may be considered to replace traditional Pt-based ORR catalysts for fuel cells, and rGO loading has been proven to be an effective strategy to enhance the ORR performance of CoP, which may provide a new idea to synthesize transition metal phosphides as ORR catalysts.


2018 ◽  
Vol 42 (3) ◽  
pp. 2081-2088 ◽  
Author(s):  
Man Zhang ◽  
Wei Hong ◽  
Ruinan Xue ◽  
Lingzhi Li ◽  
Guanbo Huang ◽  
...  

At present, low-cost and efficient electrocatalysts for accelerating the oxygen reduction reaction in fuel cells are highly desired.


2021 ◽  
Vol MA2021-02 (36) ◽  
pp. 1024-1024
Author(s):  
Hassan Shirzadi Jahromi ◽  
Shivi Saxena ◽  
Sudharsan Sridhar ◽  
Muralidhar K Ghantasala ◽  
Ramakrishna Guda ◽  
...  

2021 ◽  
Vol 104 (8) ◽  
pp. 59-71
Author(s):  
Hassan Shirzadi Jahromi ◽  
Shivi Saxena ◽  
Sudharsan Sridhar ◽  
Muralidhar K Ghantasala ◽  
Ramakrishna Guda ◽  
...  

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