Co3O4 Nanoparticles-Modified α-MnO2 Nanorods Supported on Reduced Graphene Oxide as Cathode Catalyst for Oxygen Reduction Reaction in Alkaline Media

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.

RSC Advances ◽  
2016 ◽  
Vol 6 (40) ◽  
pp. 33302-33307 ◽  
Author(s):  
Cancan Ren ◽  
Haibo Li ◽  
Rui Li ◽  
Shuling Xu ◽  
Denghu Wei ◽  
...  

1,10-Phenanthroline–cobalt(ii) metal-complex supported on rGO exhibited a high efficient four-electron catalytic activity towards ORR.


RSC Advances ◽  
2021 ◽  
Vol 11 (62) ◽  
pp. 39118-39129
Author(s):  
Fereshteh Dehghani Sanij ◽  
Prabhuraj Balakrishnan ◽  
Huaneng Su ◽  
Lindiwe Khotseng ◽  
Qian Xu

A novel nanocatalyst, polyoxometalate-modified palladium–nickel/reduced graphene oxide (Pd8Ni2/rGO-POM), is prepared and served as an effective ORR nanomaterial in alkaline media.


Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4307
Author(s):  
Oana-Andreea Lazar ◽  
Adriana Marinoiu ◽  
Mircea Raceanu ◽  
Aida Pantazi ◽  
Geanina Mihai ◽  
...  

The commonly used electrode Pt supported on a carbon (Pt/C) catalyst has demonstrated underperforming electrochemical durability in proton exchange membrane fuel cell (PEMFC) harsh operation conditions, especially in terms of Pt electrochemical instability and carbon corrosion. Gold nanoparticles (AuNPs) are considered one of the best alternative catalysts of PtNPs due to their remarkable selectivity for oxygen reduction reaction (ORR) and electrochemical stability in strong acid conditions, attributes which are ideal for practical PEMFC applications. In this work, we propose a new, facile and low-cost approach to prepare AuNPs supported on reduced graphene oxide nanocompounds (AuNPs/rGO). The morphological and structural properties of the as-prepared AuNPs/rGO were studied using various microscopic and spectroscopic techniques, namely, Raman Spectroscopy, Scanning Electron Microscopy (SEM), Scanning Transmission Electron Microscopy (STEM), X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), specific surface area (Brunauer–Emmett–Teller, BET). A mesoporous structure with narrow pore size distribution centered at 2 nm approximately, where the pores are regular and interconnected was successfully fabricated. The prepared catalyst was exposed to an accelerated stress test (potential cycles between −0.8 and +0.2 in KOH 1 M solution). The voltammetric stability test indicated a slight degradation after 1500 cycles. The electrochemical stability was assigned to the combined effect of AuNPs formed during chemical synthesis and to graphene oxide support.


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.


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