scholarly journals Synthesis and electrocatalytic activity towards oxygen reduction reaction of gold-nanostars

2018 ◽  
Vol 18 (44) ◽  
pp. 36-40
Author(s):  
Oyunbileg G ◽  
Batnyagt G ◽  
Enkhsaruul B ◽  
T Takeguchi
Keyword(s):  
Electron Microscope ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Electrocatalytic Activity ◽  
Electrical Energy ◽  
Rotating Disk ◽  
Reduction Reaction ◽  
Rotating Disk Electrode ◽  
Alkaline Electrolyte ◽  
Study Results

The oxygen reduction reaction (ORR) is a characteristic reaction which determines the performance of fuel cells which convert a chemical energy into an electrical energy. Aims of this study are to synthesize Au-based nanostars (AuNSs) and determine their preliminary electro-catalytic activities towards ORR by a rotating-disk electrode method in alkaline electrolyte. The images obtained from a scanning electron microscope (SEM) and a transmission electron microscope (TEM) analyses confirm the formation of the star-shaped nanoparticles. Among the investigated nanostar catalysts, an AuNS5 with smaller size and a few branches showed the higher electrocatalytic activity towards ORR than other catalysts with a bigger size. In addition, the electron numbers transferred for all the catalysts are approximately two. The present study results infer that the size of the Au-based nanostars may influence greatly on their catalytic activity. The present study results show that the further improvement is needed for Au-based nanostar catalysts towards the ORR reaction.

scholarly journals Perovskite-Type Oxides La0.6M0.4Ni0.6Cu0.4O3 (M = Ag, Ba, Ce) towards the Oxygen Reduction Reaction (ORR) in Alkaline Medium: Structural Aspects and Electrocatalytic Activity

2021 ◽  
Author(s):  
Alan Lima ◽  
Alex Lima ◽  
Gabriel Meloni ◽  
Carla Santos ◽  
Mauro Bertotti
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Alkaline Medium ◽  
Electrocatalytic Activity ◽  
Pechini Method ◽  
Rotating Disk ◽  
Reduction Reaction ◽  
Rotating Disk Electrode ◽  
Competition Mode ◽  
Good Catalytic Activity

In this work, La0.6M0.4Ni0.6Cu0.4O3 (M = Ag, Ba, and Ce, denoted as LANC, LBNC, and LCNC, respectively) electrocatalysts were synthesized by the Pechini method at 1023 K for two hours in air. Rietveld refinement allowed the identification of the crystallographic phases present in all oxides. The electrocatalytic performance of these oxides towards the oxygen reduction reaction (ORR) was examined in alkaline medium by rotating disk electrode (RDE) technique and scanning electrochemical microscopy (SECM) in the redox competition mode. The results indicate that the best performance was found with the LANC electrocatalyst prepared with carbon as a conducting agent (LANC/Carbon), which showed good catalytic activity towards the ORR via a pseudo fourelectron transfer pathway. The enhanced electrocatalytic activity of LANC is probably a result of the presence of a Ag phase, which improves the synergistic effect between the perovskite and carbon added to increase the conductivity, thus leading to a higher ORR performance when compared to other materials.

scholarly journals Eco-Friendly Nitrogen-Doped Graphene Preparation and Design for the Oxygen Reduction Reaction

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3858
Author(s):  
Monica Dan ◽  
Adriana Vulcu ◽  
Sebastian A. Porav ◽  
Cristian Leostean ◽  
Gheorghe Borodi ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Rotating Disk ◽  
Reduction Reaction ◽  
Machine Learning Algorithms ◽  
Rotating Disk Electrode ◽  
X Ray ◽  
Synthesis Conditions ◽  
Characterization Techniques ◽  
Doped Graphene

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.

Methanol-Tolerant Oxygen Reduction Reaction at Pt–Pd/C Alloy Nanocatalysts

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
A. Mary Remona ◽  
K. L. N. Phani
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Rotating Disk ◽  
Reduction Reaction ◽  
Rotating Disk Electrode ◽  
Methanol Tolerance ◽  
Pd Catalysts ◽  
Onset Potential ◽  
Direct Methanol ◽  
Methanol Tolerant

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.

scholarly journals Oxygen Reduction Reaction Electrocatalysis in Alkaline Electrolyte on Glassy-Carbon-Supported Nanostructured Pr6O11 Thin-Films

Catalysts ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 461 ◽  
Author(s):  
Rakesh Sharma ◽  
Verónica Müller ◽  
Marian Chatenet ◽  
Elisabeth Djurado
Keyword(s):  
Thin Films ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Glassy Carbon ◽  
Spray Deposition ◽  
Reduction Reaction ◽  
Rotating Disk Electrode ◽  
Alkaline Electrolyte ◽  
Electrochemical Performances ◽  
Electrostatic Spray Deposition

In this work, hierarchical nanostructured Pr6O11 thin-films of brain-like morphology were successfully prepared by electrostatic spray deposition (ESD) on glassy-carbon substrates. These surfaces were used as working electrodes in the rotating disk electrode (RDE) setup and characterized in alkaline electrolyte (0.1 M NaOH at 25 ± 2 °C) for the hydrogen evolution reaction (HER), the oxygen evolution reaction (OER), and the oxygen reduction reaction (ORR) for their potential application in alkaline electrolyzers or in alkaline fuel cells. The electrochemical performances of these electrodes were investigated as a function of their crystallized state (amorphous versus crystalline). Although none of the materials display spectacular HER and OER activity, the results show interesting performances of the crystallized sample towards the ORR with regards to this class of non-Pt group metal (non-PGM) electrocatalysts, the activity being, however, still far from a benchmark Pt/C electrocatalyst.

Ethanol: Tolerant Oxygen Reduction Reaction Catalysts in Alkaline Media

2018 ◽  
Vol 16 (2) ◽  
Author(s):  
Chakkrapong Chaiburi ◽  
Bernd Cermenek ◽  
Birgit Elvira Pichler ◽  
Christoph Grimmer ◽  
Viktor Hacker
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
State Of The Art ◽  
Rotating Disk ◽  
Reduction Reaction ◽  
Rotating Disk Electrode ◽  
Alkaline Media ◽  
Direct Ethanol Fuel Cells ◽  
X Ray ◽  
Transmission Electron

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.

scholarly journals N8− Polynitrogen Stabilized on Nitrogen-Doped Carbon Nanotubes as an Efficient Electrocatalyst for Oxygen Reduction Reaction

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 864 ◽  
Author(s):  
Zhenhua Yao ◽  
Ruiyang Fan ◽  
Wangyang Ji ◽  
Tingxuan Yan ◽  
Maocong Hu
Keyword(s):  
Carbon Nanotubes ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Rotating Disk ◽  
Reduction Reaction ◽  
Rotating Disk Electrode ◽  
Nitrogen Doped ◽  
Metal Free ◽  
Temperature Programmed ◽  
Nitrogen Doped Carbon

In this work, non-traditional metal-free polynitrogen chain N8− deposited on a nitrogen-doped carbon nanotubes (PN-NCNT) catalyst was successfully synthesized by a facile cyclic voltammetry (CV) approach, which was further tested in an oxygen reduction reaction (ORR). The formation of PN on NCNT was confirmed by attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR) and Raman spectroscopy. Partial positive charge of carbon within NCNT facilitated electron transfer and accordingly induced the formation of more PN species compared to CNT substrate as determined by temperature-programmed decomposition (TPD). Rotating disk electrode (RDE) measurements suggested that a higher current density was achieved over PN-NCNT than that on PN-CNT catalyst, which can be attributed to formation of the larger amount of N8− on NCNT. Kinetic study suggested a four-electron pathway mechanism over PN-NCNT. Moreover, it showed long stability and good methanol tolerance, which indicates its great potential application. This work provides insights on designing and synthesizing non-traditional metal-free catalysts for ORR in fuel cells.

scholarly journals MOF-Derived CuPt/NC Electrocatalyst for Oxygen Reduction Reaction

Catalysts ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 799 ◽  
Author(s):  
Rehan Anwar ◽  
Naseem Iqbal ◽  
Saadia Hanif ◽  
Tayyaba Noor ◽  
Xuan Shi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Photoelectron Spectroscopy ◽  
Rotating Disk ◽  
Reduction Reaction ◽  
Rotating Disk Electrode ◽  
X Ray ◽  
Onset Potential ◽  
Orr Activity

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.

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