Investigation of ORR Performances on Graphene/Phthalocyanine Nanocomposite in Neutral Medium

2019 ◽  
Vol 25 (6) ◽  
pp. 1416-1421 ◽  
Author(s):  
Moumita Mukherjee ◽  
Madhupriya Samanta ◽  
Gour P. Das ◽  
Kalyan K. Chattopadhyay

AbstractThe drive to replace scarce and expensive Pt-based electrocatalysts for oxygen reduction reaction (ORR) has led to the development of a group of electrocatalysts composed of transition-metal ion centers coordinated with four nitrogen groups (M-N4). Among these, metal phthalocyanines (MPcs), due to low cost of preparation, highly conjugated structure as well as high thermal and chemical stability, have received a great interest. The catalytic activity of MPcs can be improved by employing conducting supports. Here, in this report, we have solvothermally synthesized graphene-supported zinc phthalocyanine nanostructures, and their ORR kinetics and mechanism have been investigated in neutral solution (pH = 7) by using the rotating disk electrode technique. The as-synthesized nanocomposite followed a 4e− reduction pathway. The onset potential (−0.04 V versus Ag/AgCl) found in this work can be comparable with other state-of-the-art material, demonstrating good performance in neutral solution. The fascinating performance leads the nanocomposite material toward future energy applications.

Author(s):  
A. Mary Remona ◽  
K. L. N. Phani

Carbon-supported platinum and Pt–Pd alloy electrocatalysts with different Pt/Pd atomic ratios were synthesized by a microemulsion method at room temperature (metal loading is 10 wt %). The Pt–Pd/C bimetallic catalysts showed a single-phase fcc structure and the mean particle size of Pt–Pd/C catalysts was found to be lower than that of Pt/C. The methanol-tolerant studies of the catalysts were carried out by activity evaluation of oxygen reduction reaction (ORR) on Pt–Pd catalysts using a rotating disk electrode (RDE). The studies indicated that the order of methanol tolerance was found to be PtPd3/C>PtPd/C>Pt3Pd/C. The oxygen reduction activities of all Pt–Pd/C were considerably larger than that of Pt/C with respect to onset and overpotential values. The Pd-loaded catalysts shift the onset potential of ORR by 125 mVMSE, 53 mVMSE, and 41 mVMSE to less cathodic potentials for Pt3Pd/C, PtPd/C, and PtPd3/C, respectively, with reference to Pt/C and the Pt3Pd/C catalyst showed greater shift in the onset value than the other PtPd catalysts reported in literature. Moreover, the Pt–Pd/C catalysts exhibited much higher methanol tolerance during ORR than the Pt/C, assessing that these catalysts may function as a methanol-tolerant cathode catalysts in a direct methanol fuel cell.


Catalysts ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 799 ◽  
Author(s):  
Rehan Anwar ◽  
Naseem Iqbal ◽  
Saadia Hanif ◽  
Tayyaba Noor ◽  
Xuan Shi ◽  
...  

Metal-organic frameworks (MOFs) have been at the center stage of material science in the recent past because of their structural properties and wide applications in catalysis. MOFs have also been used as hard templates for the preparation of catalysts. In this study, highly active CuPt/NC electrocatalyst was synthesized by pyrolyzing Cu-tpa MOF along with Pt precursor under flowing Ar-H2 atmosphere. The catalyst was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray powder diffraction (XRD). Rotating disk electrode study was performed to determine the oxygen reduction reaction (ORR) activity for CuPt/NC in 0.1 M HClO4 at different revolutions per minute (400, 800, 1200, and 1600) and it was also compared with commercial Pt/C catalyst. Further the ORR performance was evaluated by K-L plots and Tafel slope. CuPt/NC shows excellent ORR performance with onset potential of 0.9 V (vs. RHE), which is comparable with commercial Pt/C. The ORR activity of CuPt/NC is demonstrated as an efficient electrocatalyst for fuel cell.


2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Zheng Gong ◽  
Guoquan Zhang ◽  
Song Wang

The electrochemical behaviors of monohydroxy-anthraquinone/multiwall carbon nanotubes (MHAQ/MWCNTs) nanohybrid modified glassy carbon (MHAQ/MWCNTs/GC) electrodes in neutral medium were investigated; also reported was their application in the electrocatalysis of oxygen reduction reaction (ORR). The resulting MHAQ/MWCNTs nanohybrid was characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM). It was found that the ORR at the MHAQ/MWCNTs/GC electrode occurs irreversibly at a potential about 214 mV less negative than at a bare GC electrode in pH 7.0 buffer solution. Cyclic voltammetric and rotating disk electrode (RDE) techniques indicated that the MHAQ/MWCNTs nanohybrid has high electrocatalytic activity for the two-electron reduction of oxygen in the studied potential range. The kinetic parameters of ORR at the MHAQ/MWCNTs nanohybrid modified GC electrode were also determined by RDE and EIS techniques.


2009 ◽  
Vol 7 (4) ◽  
pp. 739-744 ◽  
Author(s):  
Rūta Araminaitė ◽  
Rasa Garjonytė ◽  
Albertas Malinauskas

AbstractElectrooxidation of ascorbate has been studied with the use of a rotating disk electrode. The results obtained show an efficient electrocatalytic oxidation of ascorbate at the Prussian blue (PB) modified electrode to proceed in solutions of pH 5.5 and 7.3. Depending on solution pH, the onset potential for ascorbate electrooxidation at PB modified electrode appears shifted by 0.1–0.2 V to lower values, as compared to an unmodified glassy carbon electrode. Within the electrode potential window of 0.3 to 0.5 V vs. Ag/AgCl, and electrode rotation velocity of 50–2000 rpm, the catalytic current obeys Koutecky-Levich equation at a submillimolar ascorbate concentration. Kinetic current densities, obtained from the data treatment, are higher for a pH 5.5 solution, and also at higher electrode potential.


Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3858
Author(s):  
Monica Dan ◽  
Adriana Vulcu ◽  
Sebastian A. Porav ◽  
Cristian Leostean ◽  
Gheorghe Borodi ◽  
...  

Four N-doped graphene materials with a nitrogen content ranging from 8.34 to 13.1 wt.% are prepared by the ball milling method. This method represents an eco-friendly mechanochemical process that can be easily adapted for industrial-scale productivity and allows both the exfoliation of graphite and the synthesis of large quantities of functionalized graphene. These materials are characterized by transmission and scanning electron microscopy, thermogravimetry measurements, X-ray powder diffraction, X-ray photoelectron and Raman spectroscopy, and then, are tested towards the oxygen reduction reaction by cyclic voltammetry and rotating disk electrode methods. Their responses towards ORR are analysed in correlation with their properties and use for the best ORR catalyst identification. However, even though the mechanochemical procedure and the characterization techniques are clean and green methods (i.e., water is the only solvent used for these syntheses and investigations), they are time consuming and, generally, a low number of materials can be prepared, characterized and tested. In order to eliminate some of these limitations, the use of regression learner and reverse engineering methods are proposed for facilitating the optimization of the synthesis conditions and the materials’ design. Thus, the machine learning algorithms are applied to data containing the synthesis parameters, the results obtained from different characterization techniques and the materials response towards ORR to quickly provide predictions that allow the best synthesis conditions or the best electrocatalysts’ identification.


2005 ◽  
Vol 900 ◽  
Author(s):  
Peter N. Njoki ◽  
Jin Luo ◽  
Aisley Jacob ◽  
Rizwan Munawar ◽  
Bilal Khan ◽  
...  

ABSTRACTThe ability to control composition and size in the synthesis of bimetallic nanoparticles is important for the exploitation of the bimetallic catalytic properties. This paper reports recent findings of an investigation of the synthesis of gold-platinum (AuPt) bimetallic nanoparticles in aqueous solution via reduction of AuCl4− and PtCl42− using a combination of reducing and capping agents. In addition to characterization of the morphological properties of the AuPt nanoparticles using TEM and XRD, the electrocatalytic activity of the carbon-supported AuPt nanoparticle catalysts was also examined for oxygen reduction reaction (ORR) using the rotating disk electrode (RDE) technique. The findings have implications to the design of bimetallic nanoparticle catalysts for fuel cell reactions.


Author(s):  
Chakkrapong Chaiburi ◽  
Bernd Cermenek ◽  
Birgit Elvira Pichler ◽  
Christoph Grimmer ◽  
Viktor Hacker

This paper describes electrocatalysts for the oxygen reduction reaction (ORR) in alkaline direct ethanol fuel cells (ADEFCs), using the non-noble metal electrocatalyst Ag/C, MnO2/C and AgMnO2/C. These electrocatalysts showed tolerance toward ethanol in alkaline media and therefore resistance to ethanol crossover in ADEFCs. Transmission electron microscopy, X-ray spectroscopy (EDX), cyclic voltammetry, and rotating disk electrode (RDE) were employed to determine the morphology, composition, and electrochemical activity of the catalysts. The herein presented results confirm that the AgMnO2/C electrocatalyst significantly outperforms the state-of-the art ORR catalyst platinum.


2015 ◽  
Vol 1777 ◽  
pp. 1-6 ◽  
Author(s):  
Elaheh Davari ◽  
Douglas G. Ivey

ABSTRACTBifunctional electrocatalysts, which facilitate the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), are vital components in advanced metal-air batteries. Results are presented for carbon-free, nanocrystalline, rod-like, Mn-Co oxide/PEDOT bifunctional electrocatalysts, prepared by template-free sequential anodic electrodeposition. Electrochemical characterization of synthesized electrocatalysts, with and without a conducting polymer (PEDOT) coating, was performed using cyclic voltammetry (CV) and linear sweep voltammetry (LSV). In addition, microstructural characterization was conducted using SEM, TEM, STEM and XPS. Mn-Co oxide/PEDOT showed improved ORR/OER performance relative to Mn-Co oxide and PEDOT. On the basis of rotating disk electrode (RDE) experiments, Mn-Co oxide/PEDOT displayed the desired 4-electron transfer oxygen reduction pathway. Comparable ORR activity and superior OER activity relative to commercial Pt/C were observed.


2021 ◽  
Vol 875 ◽  
pp. 193-199
Author(s):  
Ahmad Shahbaz ◽  
Ali Afaf ◽  
Nawaz Tahir ◽  
Ullah Abid ◽  
Saher Saim

A highly active Platinum Group Metal (PGM) and non-PGM electrocatalysts with thermally extruded nanotubes have been prepared for Proton Exchange Membrane (PEM) fuel cell by sintering Nickel zeolitic imidazole framework (Ni-ZIF). Preeminent electro-catalytic activities have been observed through single fuel cell tests and rotating disk electrode (RDE). This study involves the comparison of Oxygen Reduction Reaction (ORR) activities and fuel cell (FC) test station performance of two catalyst Nickel and Platinum mixed Nickel nanotubes (Ni NT, Ni/Pt NT) respectively. The acidic cells with corresponding Ni and Ni/Pt catalysts delivers peak power densities of 325 mWcm-2 and 455 mWcm-2 at 75 °C inside fuel cell. Our results indicate that, the synthesized Nickel nanotubes has profound effect on catalytic performance of both PGM and non-PGM electro catalysts.


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