Advanced search


Knowledge area




Filter by:

Publication type

Authors

Issue Years

Publishers

Origin repository

Access Level

Language

Subject

Select the topics of your interest and receive the hottest publications in your email

2 results, page 1 of 1

A Proposal based on quantum phenomena for the ORR mechanism on Nitrogen-doped Carbon-based electrocatalysts. A DFT study

ANA MARISELA LEGARRETA MENDOZA NORMA ROSARIO FLORES HOLGUIN VIRGINIA HIDALINA COLLINS MARTINEZ DANIEL LARDIZABAL GUTIERREZ (2017)

Several theories attempt to explain how nitrogen-doped carbon-based electrocatalysts

work during the oxygen reduction reaction (ORR). However, no consensus has been

reached on which of the proposedmechanisms is the most accurate. The present work

aims to establish a hypothesis of this mechanism, based on the hybridization change of

graphene lattice carbons, from sp2 to sp3. As shown in several studies, carbons with sp3

hybridization are able to store electrons (i.e. work as capacitors), this phenomenon, along

with nitrogen inversion, due tolattice defects, presumably allows nitrogen to work as a

switch, by letting pass or stopping the flow of electrons, thus generating active sites to

enhance the ORR. Computational chemistry has been propose to prove this hypothesis.

Ninety-two doped and undopedgraphene atomswere constructed using the Gaussian View

5.0® program and geometries optimized by applying the DFT in Gaussian 09® program, to

compare lattice changes in bond angles and lengths. The obtained results did not present

significant changes to help demonstrating the hypothesis. The understanding of this

phenomenon will allow to evaluatethe feasibility of continuing the study and development

of these type of materials or if they have reached their limit as low-cost electrocatalysts.

Conference proceedings

ORR BIOLOGÍA Y QUÍMICA QUÍMICA QUÍMICA FÍSICA OTRAS

Study of the catalytic activity for oxygen reduction of polythiophene modified with cobalt or nickel

RITA DEL ROSARIO SULUB SULUB WENCESLAO MARTINEZ MILLAN MASCHA AFRA SMIT (2009)

Carbon black supported materials based on polythiophene and cobalt or nickel were studied as oxygen reduction catalysts. Polythiophene was chemically polymerized onto carbon black, and modified with cobalt or nickel salts to obtain carbon supported polythiophene-cobalt and polythiophene-nickel. For reasons of comparison, the precursor, unmodified carbon-supported polythiophene was studied, as well as unsupported polythiophene particles. In order to study the physical, chemical and electrochemical properties, TGA, SEM, EDAX and electrochemical methods were used. SEM images show porous materials with a particle size of around 110 nm for the carbon supported materials. EDAX tests confirmed the presence of approximately 7 wt% of either cobalt or nickel in the modifiedmaterials. Cyclic voltammetry confirmed the presence of ORR peaks in the cathodic area in all materials, except for polythiophene only. Based on kinetic parameters obtained using RDE tests and on electrochemical stability as determined from potentiostatic test, it was concluded that the material with best ORR catalytic activity is carbon supported polythiophene-cobalt. 

Article

CARBON-SUPPORTED CATALYST COBALT NICKEL OXYGEN REDUCTION REACTION (ORR) POLYTHIOPHENE INGENIERÍA Y TECNOLOGÍA