Open AccessA Superoxide Involved Oxygen Reduction Reaction Mechanism on a Glassy Carbon Electrode in Caustic Media
Author(s) -
Victoria F. Mattick,
Xinfang Jin,
Ralph E. White,
Kevin Huang
Publication year - 2020
Publication title -
journal of the electrochemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.258
H-Index - 271
eISSN - 1945-7111
pISSN - 0013-4651
DOI - 10.1149/1945-7111/ababd4
Subject(s) - oxygen , peroxide , glassy carbon , superoxide , chemistry , electrode , electrochemistry , hydroxide , carbon fibers , inorganic chemistry , redox , oxygen reduction , hydrogen peroxide , materials science , organic chemistry , cyclic voltammetry , composite material , composite number , enzyme
In this work, a plain glassy carbon electrode has been investigated as a base platform to build a superoxide-ion-involved, 2-dimensional, multi-physics model to describe its oxygen reduction mechanism in caustic media. A rotating ring disk technique has been used to quantify the peroxide content and to compare the results predicted by a general multiphysics model, which was further used to extract the influencing kinetic parameters. There are three proposed models involving different mechanism combinations made up of: a sequential, single electron reduction of oxygen to superoxide, then to peroxide; a sequential two electron reduction of oxygen to peroxide followed by the final reduction to hydroxide; and a direct four electron reduction of oxygen straight to hydroxide. One model stands out to be the best description for the multistep oxygen reduction behavior of the glassy carbon electrode in 0.1 M KOH with very satisfactory results, which yields a series of important electrode kinetic transfer coefficients and exchange current densities for the elementary electrochemical reactions considered.