scholarly journals Chirality enhances oxygen reduction

2021 ◽  
Author(s):  
Yutao Sang ◽  
Francesco Tassinari ◽  
Kakali Santra ◽  
Wenyan Zhang ◽  
David Waldeck ◽  
...  
Keyword(s):  
Oxygen Reduction ◽  
Ground State ◽  
Clean Energy ◽  
Reduction Reaction ◽  
Spin Orbit Coupling ◽  
Triplet Ground State ◽  
Energy Technologies ◽  
Singlet States ◽  
Oxygen Oxygen ◽  
Current Densities

Abstract Controlled reduction of oxygen is important for developing clean energy technologies, such as fuel cells, and is vital to the existence of aerobic organisms. The process starts with oxygen in a triplet ground state and ends with products that are all in singlet states. Hence, spin constraints in the oxygen reduction must be considered. Here we show that electron transfer from chiral electrodes to oxygen (oxygen reduction reaction) is enhanced over that from achiral electrodes. We demonstrate lower overpotentials and higher current densities for chiral catalysts versus achiral ones. This finding holds even for electrodes composed of heavy metals with large spin orbit coupling. The effect results from the spin selectivity conferred on the electron current by the chiral assemblies, the chiral induced spin selectivity effect.

Understanding the mechanisms and design principles for oxygen evolution and oxygen reduction activity on perovskite catalysts for alkaline zinc–air batteries

2021 ◽  
Author(s):  
Oyunbileg Galindev ◽  
Tatsuya Takeguchi ◽  
Md. Mijanur Rahman
Keyword(s):  
Oxygen Reduction ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Precious Metal ◽  
Clean Energy ◽  
Reduction Reaction ◽  
Energy Technologies ◽  
Reduction Activity ◽  
Precious Metal Catalysts ◽  
Zinc Air Batteries

The high cost and limited availability of the precious metal catalysts required for catalysing the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) in metal–air batteries restrict the marketing of these clean energy technologies.

Topological defects involving Fe/N co-doped mesoporous carbon nanosheets as novel electrocatalysts for the oxygen reduction reaction and Zn–air batteries

Nanoscale ◽  
2021 ◽  
Author(s):  
Junjie Ding ◽  
Dongchuang Wu ◽  
Senhe Huang ◽  
Chenbao Lu ◽  
Yu Chen ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Topological Defects ◽  
Reduction Reaction ◽  
Defect Engineering ◽  
Carbon Nanosheets ◽  
Renewable Energy Technologies ◽  
Central Focus ◽  
Energy Technologies ◽  
Co Doped

Developing effective electrocatalysts for oxygen reduction reaction is of great significance for clean and renewable energy technologies, such as metal–air batteries and fuel cells. Defect engineering is the central focus...

Mechanism of Electrochemical Oxygen Reduction Reaction at Two-Dimensional Pt-doped MoSe2 Material: An Efficient Electrocatalyst

2021 ◽  
Author(s):  
Shrish Nath Upadhyay ◽  
Srimanta Pakhira
Keyword(s):  
Fuel Cells ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Clean Energy ◽  
Reduction Reaction ◽  
Electrochemical Reactions ◽  
Two Dimensional ◽  
O2 Reduction ◽  
Energy Conversion Systems ◽  
Electrochemical Oxygen

The O2 reduction reaction (ORR) is one promising reaction in clean energy conversion systems such as fuel cells, metal-air batteries, electrochemical reactions, etc. Pt shows excellent electrocatalytic activities for ORR,...

scholarly journals N–doped hierarchical porous carbon nanoscrolls towards efficient oxygen reduction reaction in Zn–air batteries via interior and exterior modification

2021 ◽  
Author(s):  
Binhong He ◽  
Yangyang Chen ◽  
Da Hu ◽  
Ziyan Wen ◽  
Minjie Zhou ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Rational Design ◽  
Clean Energy ◽  
Reduction Reaction ◽  
Hierarchical Porous Carbon ◽  
Hierarchical Porous ◽  
Carbon Nanoscrolls ◽  
Energy Conversion Devices

Rational design of oxygen reduction reaction (ORR) electrocatalysts is essential for promoting the development of clean energy conversion devices. Herein, we report an in–situ sacrificial template strategy combining with external...

scholarly journals N-doped carbon nanomaterials are durable catalysts for oxygen reduction reaction in acidic fuel cells

2015 ◽  
Vol 1 (1) ◽  
pp. e1400129 ◽  
Author(s):  
Jianglan Shui ◽  
Min Wang ◽  
Feng Du ◽  
Liming Dai
Keyword(s):  
Fuel Cells ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Carbon Nanomaterials ◽  
Low Cost ◽  
Clean Energy ◽  
Pem Fuel Cells ◽  
Reduction Reaction ◽  
Metal Free ◽  
Carbon Based

The availability of low-cost, efficient, and durable catalysts for oxygen reduction reaction (ORR) is a prerequisite for commercialization of the fuel cell technology. Along with intensive research efforts of more than half a century in developing nonprecious metal catalysts (NPMCs) to replace the expensive and scarce platinum-based catalysts, a new class of carbon-based, low-cost, metal-free ORR catalysts was demonstrated to show superior ORR performance to commercial platinum catalysts, particularly in alkaline electrolytes. However, their large-scale practical application in more popular acidic polymer electrolyte membrane (PEM) fuel cells remained elusive because they are often found to be less effective in acidic electrolytes, and no attempt has been made for a single PEM cell test. We demonstrated that rationally designed, metal-free, nitrogen-doped carbon nanotubes and their graphene composites exhibited significantly better long-term operational stabilities and comparable gravimetric power densities with respect to the best NPMC in acidic PEM cells. This work represents a major breakthrough in removing the bottlenecks to translate low-cost, metal-free, carbon-based ORR catalysts to commercial reality, and opens avenues for clean energy generation from affordable and durable fuel cells.

L2,3-edges absorption spectra of a 2D complex system: a theoretical modelling

2016 ◽  
Vol 18 (40) ◽  
pp. 28110-28116 ◽  
Author(s):  
S. Carlotto ◽  
M. Sambi ◽  
F. Sedona ◽  
A. Vittadini ◽  
J. Bartolomé ◽  
...  
Keyword(s):  
Complex System ◽  
Electron Transfer ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Absorption Spectra ◽  
Ground State ◽  
Reduction Reaction ◽  
Theoretical Modelling ◽  
Electron Transfer Pathway ◽  
System A

Ground state theoretical outcomes pertaining to FePc (I) and FePc(η2-O2) (II) provide an intimate understanding of the electron transfer pathway ruling the catalytic oxygen reduction reaction of I on Ag(110).

scholarly journals Temperature dependence of the kinetics of oxygen reduction on carbon-supported pt nanoparticles

2008 ◽  
Vol 73 (6) ◽  
pp. 641-654 ◽  
Author(s):  
Nevenka Elezovic ◽  
Biljana Babic ◽  
Nedeljko Krstajic ◽  
Snezana Gojkovic ◽  
Ljiljana Vracar
Keyword(s):  
Temperature Dependence ◽  
Oxygen Reduction ◽  
Current Density ◽  
Pt Nanoparticles ◽  
Reduction Reaction ◽  
Hydrogen Electrode ◽  
Rate Determining Step ◽  
Current Densities ◽  
Kinetics Of ◽  
Mechanism Of The Reaction

The temperature dependence of oxygen reduction reaction (ORR) was studied on highly dispersed Pt nanoparticles supported on a carbon cryo-gel. The specific surface area of the support was 517 m2 g-1, the Pt particles diameter was about 2.7 nm and the loading of the catalyst was 20 wt.%. The kinetics of the ORR at the Pt/C electrode was examined in 0.50 mol dm-3 HClO4 solution in the temperature range from 274 to 318 K. At all temperatures, two distinct E-log j regions were observed; at low current densities with a slope of -2.3RT/F and at high current densities with a slope of -2.3?2RT/F. In order to confirm the mechanism of oxygen reduction previously suggested at a polycrystalline Pt and a Pt/Ebonex nanostructured electrode, the apparent enthalpies of activation at selected potentials vs. the reversible hydrogen electrode were calculated in both current density regions. Although ?H ?a,1 > ?H ?a,h , it was a,1 a, h found that the enthalpies of activation at the zero Galvani potential difference were the same and hence it could be concluded that the rate-determining step of the ORR was the same in both current density regions. The synthesized Pt/C catalyst showed a small enhancement in the catalytic activity for ORR in comparison to the polycrystalline Pt, but no change in the mechanism of the reaction.

scholarly journals Oxygen reduction at platinum nanoparticles supported on carbon cryogel in alkaline solution

2007 ◽  
Vol 72 (7) ◽  
pp. 699-708 ◽  
Author(s):  
N.R. Elezovic ◽  
B.M. Babic ◽  
LJ.M. Vracar ◽  
N.V. Krstajic
Keyword(s):  
Particle Size ◽  
Oxygen Reduction ◽  
Alkaline Solution ◽  
Reduction Reaction ◽  
Rotating Disc ◽  
Rate Determining Step ◽  
Naoh Solution ◽  
Orr Kinetics ◽  
Carbon Cryogel ◽  
Current Densities

The oxygen reduction reaction was investigated in 0.1 M NaOH solution, on a porous coated electrode formed of Pt particles supported on carbon cryogel. The Pt/C catalyst was characterized by the X-ray diffraction (XRD), transmission electron microscopy (TEM) and cyclic voltammetry techniques. The results demonstrated a successful reduction of Pt to metallic form and homogenous Pt particle size distribution with a mean particle size of about 2.7 nm. The ORR kinetics was investigated by linear sweep polarization at a rotating disc electrode. The results showed the existence of two E - log j regions, usually referred to polycrystalline Pt in acid and alkaline solution. At low current densities (lcd), the Tafel slope was found to be close to -2.3RT/F, while at high current densities (hcd) it was found to be close to -2?2.3RT/F. It is proposed that the main path in the ORR mechanism on Pt particles was the direct four-electron process, with the transfer of the first electron as the rate determining step. If the activities are expressed through the specific current densities, a small enhancement of the catalytic activity for Pt/C was observed compared to that of polycrystalline Pt. The effect of the Pt particle size on the electrocatalysis of oxygen reduction was ascribed to the predominant (111) facets of the platinum crystallites. .

scholarly journals Morphology and Structure Controls of Single-Atom Fe–N–C Catalysts Synthesized Using FePc Powders as the Precursor

Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 109
Author(s):  
Ning Yan ◽  
Fan Liu ◽  
Xu Meng ◽  
Meng Qin ◽  
Guangqi Zhu ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Pressure Control ◽  
Reduction Reaction ◽  
Single Atom ◽  
Root Cause ◽  
Organic Vapor ◽  
Current Densities ◽  
Temperature And Pressure ◽  
The Difference

Understanding the origin of the high electrocatalytic activity of Fe–N–C electrocatalysts for oxygen reduction reaction is critical but still challenging for developing efficient sustainable nonprecious metal catalysts used in fuel cells. Although there are plenty of papers concerning the morphology on the surface Fe–N–C catalysts, there is very little work discussing how temperature and pressure control the growth of nanoparticles. In our lab, a unique organic vapor deposition technology was developed to investigate the effect of the temperature and pressure on catalysts. The results indicated that synthesized catalysts exhibited three kinds of morphology—nanorods, nanofibers, and nanogranules—corresponding to different synthesis processes. The growth of the crystal is the root cause of the difference in the surface morphology of the catalyst, which can reasonably explain the effect of the temperature and pressure. The oxygen reduction reaction current densities of the different catalysts at potential 0.88 V increased in the following order: FePc (1.04 mA/cm2) < Pt/C catalyst (1.54 mA/cm2) ≈ Fe–N–C-f catalyst (1.64 mA/cm2) < Fe–N–C-g catalyst (2.12 mA/cm2) < Fe–N–C-r catalyst (2.35 mA/cm2). By changing the morphology of the catalyst surface, this study proved that the higher performance of the catalysts can be obtained.

scholarly journals Conducting Copper(I/II)-Metallopolymer for the Electrocatalytic Oxygen Reduction Reaction (ORR) with High Kinetic Current Density

Polymers ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1002 ◽  
Author(s):  
Sait Elmas ◽  
Wesley Beelders ◽  
Xun Pan ◽  
Thomas Nann
Keyword(s):  
Fuel Cell ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Noble Metals ◽  
Reduction Reaction ◽  
Rotating Disk Electrode ◽  
Potential Candidate ◽  
Hydrogen Electrode ◽  
Electrocatalytic Oxygen Reduction ◽  
Current Densities

The oxygen reduction reaction (ORR) is still the most research-intensive aspect of a fuel cell. The sluggish kinetics of the electrocatalysts toward the ORR requires large amounts of platinum to be used as cathode material, which calls for alternatives to replace or minimize the amount of the noble metals used. This study describes the synthesis and complete characterization of a copper metallopolymer (Cu MP) based on a conducting polymer (CP) and single-site catalytic centers for the electrocatalytic ORR. The copper (II) catalyst, embedded in a redox-active and conducting polymeric environment, was pursued as a potential candidate to replace noble metals in fuel cell applications. Performance studies at a rotating disk electrode (RDE) showed that the metallopolymer exhibited a direct four-electron reduction at potentials between −150 and −350 mV vs. the reversible hydrogen electrode (RHE) and high kinetic current densities of over 22.62 mA/cm2. The kinetic current densities obtained at the Cu MP electrode outperformed most of the reported state-of-the art electrocatalysts toward the ORR. Further analysis of the Cu/CP hybrid revealed the copper being largely reduced to the oxidation state +I.

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