scholarly journals Improvement of Catalytic Activity of Platinum Nanoparticles Decorated Carbon Graphene Composite on Oxygen Electroreduction for Fuel Cells

Processes ◽  
2019 ◽  
Vol 7 (9) ◽  
pp. 586 ◽  
Author(s):  
Halima Begum ◽  
Young-Bae Kim
Keyword(s):  
Catalytic Activity ◽  
Fuel Cells ◽  
Surface Area ◽  
High Performance ◽  
Pt Nanoparticles ◽  
Reduction Reaction ◽  
Graphene Sheets ◽  
Crossover Effect ◽  
Onset Potential ◽  
Monolayer Dispersion

High-performance platinum (Pt)-based catalyst development is crucially important for reducing high overpotential of sluggish oxygen reduction reaction (ORR) at Pt-based electrocatalysts, although the high cost and scarcity in nature of Pt are profoundly hampering the practical use of it in fuel cells. Thus, the enhancing activity of Pt-based electrocatalysts with minimal Pt-loading through alloy, core−shell or composite making has been implemented. This article deals with enhancing electrocatalytic activity on ORR of commercially available platinum/carbon (Pt/C) with graphene sheets through a simple composite making. The Pt/C with graphene sheets composite materials (denoted as Pt/Cx:G10−x) have been characterized by several instrumental measurements. It shows that the Pt nanoparticles (NPs) from the Pt/C have been transferred towards the π-conjugated systems of the graphene sheets with better monolayer dispersion. The optimized Pt/C8:G2 composite has higher specific surface area and better degree of graphitization with better dispersion of NPs. As a result, it shows not only stable electrochemical surface area but also enhanced ORR catalytic activity in respect to the onset potential, mass activity and electron transfer kinetics. As shown by the ORR, the Pt/C8:G2 composite is also better resistive to the alcohol crossover effect and more durable than the Pt/C.

Enhancing Oxygen Reduction Reaction Activity of α-MnO2 Nanowires Through Ag Doping

NANO ◽  
2020 ◽  
Vol 15 (09) ◽  
pp. 2050115
Author(s):  
Zixu Wu ◽  
Guangxing Li ◽  
Qin Liao ◽  
Ruida Ding ◽  
Xuze Zuo ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Fuel Cells ◽  
Oxygen Reduction Reaction ◽  
Manganese Oxide ◽  
Oxygen Reduction ◽  
High Performance ◽  
Large Scale ◽  
Reaction Pathway ◽  
Reduction Reaction ◽  
Ag Doping

Enhancing the catalytic activity of manganese oxide in oxygen reduction reaction (ORR) is a key issue for its large-scale application in metal-air fuel cells. Ag-doped [Formula: see text]-MnO2 nanowires without Ag or Ag2O have been successfully synthesized via a facile hydrothermal method, and the changes in both the structure and electrochemical catalytic performances after Ag doping are investigated. Compared with the pristine [Formula: see text]-MnO2, the as-prepared Ag-doped MnO2 exhibits a significantly enhanced catalytic activity in both ORR and Mg-air fuel cell application. With Ag/Mn ratio of 1:25, Ag-doped MnO2 exhibits a typical 4e-reaction pathway and presents a 163 mV higher half-wave potential than that of the pristine [Formula: see text]-MnO2. Furthermore, it demonstrates a power density of 75.1[Formula: see text]mW[Formula: see text]cm[Formula: see text] at current density of 134.5[Formula: see text]mA[Formula: see text]cm[Formula: see text] in the Mg-air fuel cells. The enhanced ORR performances are considered to be contributed from the activation of surface lattice oxygen, the improvement in conductivity and the increase in oxygen vacancies of [Formula: see text]-MnO2. These findings provide new understanding for developing high-performance manganese oxide catalysts.

scholarly journals Optimisation Study of Co Deposition on Chars from MAP of Waste Tyres as Green Electrodes in ORR for Alkaline Fuel Cells

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5646
Author(s):  
Maurizio Passaponti ◽  
Leonardo Lari ◽  
Marco Bonechi ◽  
Francesca Bruni ◽  
Walter Giurlani ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Fuel Cells ◽  
Electrochemical Deposition ◽  
Noble Metals ◽  
Reduction Reaction ◽  
Structure Evolution ◽  
Alkaline Fuel Cells ◽  
Onset Potential ◽  
Electro Catalysis ◽  
Scanning Transmission

Oxygen Reduction Reaction (ORR) catalysts, from waste automobile tyres obtained from Microwave assisted pyrolysis (MAP), were enriched with Co and Cu using the simple treatments sonochemical and electrochemical deposition. Catalytic activity was evaluated through onset potential and number of exchanged electrons measurements. Electrochemical data demonstrate an improvement in catalytic activity of the electrochemical modified char with Co. Char electrodes enriched with Co show a maximum positive shift of 40 mV with respect to raw char electrodes with a number of exchanged electrons per O2 molecule close to 4 (as for Pt) for the best sample. This corresponds to a reduction of the production of unwanted oxygen peroxide from 23% for raw char to 1%. Sample structure evolution before and after electrochemical deposition and electro-catalysis was investigated by scanning transmission electron microscopy and XPS. Such electrochemical treatments open new possibilities of refining waste chars and finding an economic alternative to noble metals-based catalysts for alkaline fuel cells.

Pt-CeOx/MWCNT electrocatalysts as ethanol-tolerant ORR cathodes for Direct Alcohol Fuel Cells

2011 ◽  
Vol 14 (2) ◽  
pp. 75-80 ◽  
Author(s):  
F. J. Rodriguez Varela ◽  
A. A. Gaona Coronado ◽  
J. C. Loyola ◽  
Qi-Zhong Jiang ◽  
P. Bartolo Perez
Keyword(s):  
High Performance ◽  
Average Particle Size ◽  
Weight Ratio ◽  
Pt Nanoparticles ◽  
Reduction Reaction ◽  
Average Particle ◽  
Peak Current Density ◽  
Multiwalled Carbon ◽  
Onset Potential ◽  
Direct Alcohol Fuel Cells

High performance 20% Pt-CeOx (1:1 Pt:Ce weight ratio) electrocatalyst dispersed on Multiwalled Carbon Nanotubes (MWCNTs) was synthesized under H2 atmosphere at 300 °C. The average particle size determined from XRD was ca. 1.7 and 10 nm for Ce and Pt, respectively. HRTEM analysis confirmed the presence of particle sizes within this range, although it was not possible to distinguish Ce from Pt nanoparticles. The XPS spectrum of Ce showed characteristics that indicate the existence of both oxidized and reduced phases (i.e., Ce2O3 and CeO2). It is suggested that the presence of the C3+ state establishes the capacity of this material to act as a tolerant cathode. The spectrum of Pt confirmed the presence of Pt metal. The 20% Pt-CeOx/MWCNT cathode showed high electroactivity for the Oxygen Reduction Reaction (ORR). Moreover, this novel material presented a high degree of tolerance to ethanol. During polarization tests in ethanol-containing solution, the Pt-CeOx/MWCNT cathode showed no peak current density due to the ethanol oxidation reaction (EOR) and the onset potential for the ORR shifted by only 80 mV towards more negative potentials. Thus, the presence of ceria clearly enhanced the electrochemical tolerance of the Pt-based cathode to ethanol.

Ferrocene-based porous organic polymer derived high-performance electrocatalysts for oxygen reduction

2017 ◽  
Vol 5 (42) ◽  
pp. 22163-22169 ◽  
Author(s):  
Baolong Zhou ◽  
Liangzhen Liu ◽  
Pingwei Cai ◽  
Guang Zeng ◽  
Xiaoqiang Li ◽  
...  
Keyword(s):  
Schiff Base ◽  
Catalytic Activity ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Porous Carbon ◽  
High Performance ◽  
Reduction Reaction ◽  
Organic Polymer ◽  
Porous Organic Polymers ◽  
Porous Organic Polymer

Two nitrogen-rich porous organic polymers (POPs) were prepared via Schiff base chemistry. Carbonization of these POPs results in porous carbon nanohybrids which exhibit excellent catalytic activity toward the oxygen reduction reaction (ORR).

Unravelling the Origin of Bifunctional OER/ORR Activity for Single-Atom Catalysts Supported on C2N by DFT and Machine Learning

2021 ◽  
Author(s):  
Yiran Ying ◽  
Ke Fan ◽  
Xin Luo ◽  
Jinli Qiao ◽  
Haitao Huang
Keyword(s):  
Machine Learning ◽  
Fuel Cells ◽  
Oxygen Evolution ◽  
High Performance ◽  
Reduction Reaction ◽  
Single Atom ◽  
Orr Activity

Designing high-performance bifunctional oxygen evolution/reduction reaction (OER/ORR) catalysts is a newly emerged topic with wide applications in metal-air batteries and fuel cells. Herein, we report a group of (27) single-atom...

Facile deposition of Pt nanoparticles on Sb-doped SnO2 support with outstanding active surface area for the oxygen reduction reaction

2018 ◽  
Vol 8 (10) ◽  
pp. 2672-2685 ◽  
Author(s):  
Rhiyaad Mohamed ◽  
Tobias Binninger ◽  
Patricia J. Kooyman ◽  
Armin Hoell ◽  
Emiliana Fabbri ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Surface Area ◽  
Pt Nanoparticles ◽  
Active Surface ◽  
Reduction Reaction ◽  
Active Surface Area

Synthesis of Sb–SnO2 supported Pt nanoparticles with an outstanding ECSA for the oxygen reduction reaction.

scholarly journals Improving the Performance of Zn-Air Batteries with N-Doped Electroexfoliated Graphene

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2115 ◽  
Author(s):  
Anna Ilnicka ◽  
Malgorzata Skorupska ◽  
Piotr Romanowski ◽  
Piotr Kamedulski ◽  
Jerzy P. Lukaszewicz
Keyword(s):  
Catalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Noble Metals ◽  
Electrode Materials ◽  
Low Cost ◽  
Rapid Development ◽  
Reduction Reaction ◽  
Graphene Sheets ◽  
High Catalytic Activity ◽  
Energy Storage Devices

The constantly growing demand for active, durable, and low-cost electrocatalysts usable in energy storage devices, such as supercapacitors or electrodes in metal-air batteries, has triggered the rapid development of heteroatom-doped carbon materials, which would, among other things, exhibit high catalytic activity in the oxygen reduction reaction (ORR). In this article, a method of synthesizing nitrogen-doped graphene is proposed. Few-layered graphene sheets (FL-graphene) were prepared by electrochemical exfoliation of commercial graphite in a Na2SO4 electrolyte with added calcium carbonate as a separator of newly-exfoliated FL-graphene sheets. Exfoliated FL-graphene was impregnated with a suspension of green algae used as a nitrogen carrier. Impregnated FL-graphene was carbonized at a high temperature under the flow of nitrogen. The N-doped FL-graphene was characterized through instrumental methods: high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. Electrochemical performance was determined using cyclic voltamperometry and linear sweep voltamperometry to check catalytic activity in ORR. The N-doped electroexfoliated FL-graphene obeyed the four-electron transfer pathways, leading us to further test these materials as electrode components in rechargeable zinc-air batteries. The obtained results for Zn-air batteries are very important for future development of industry, because the proposed graphene electrode materials do not contain any heavy and noble metals in their composition.

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