Open AccessMeasurement of the Stoichiometry of Ethanol Oxidation at Elevated Temperatures
Author(s) -
Azam Sayadi,
Peter G. Pickup
Publication year - 2021
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/ac035c
Subject(s) - stoichiometry , ethanol , chemistry , ethanol fuel , electrolysis , selectivity , catalysis , analytical chemistry (journal) , inorganic chemistry , electrode , organic chemistry , electrolyte
The stoichiometry of ethanol oxidation (average number of electrons transferred per molecule) is a crucial parameter in fundamental studies of ethanol oxidation and the development of direct ethanol fuel cells and electrolysis cells. Measurements of stoichiometry are particularly important at elevated temperatures, where these cells become more efficient. In this work, rotating disk and flow cell methods have been used to explore the temperature dependence of ethanol oxidation at Pt/C and PtRu/C electrodes. Stoichiometries determined from the slopes of Koutecky–Levich plots ranged from 2.1 to 2.8 at 24 °C and increased to a range of 3.4 to 5.6 at 80 °C. They were higher for PtRu/C, and increased more with increasing temperature. At 80 °C, there was a significant decrease in stoichiometry with increasing potential at both catalysts, indicating a decrease in selectivity for the complete oxidation of ethanol to CO 2 . Analysis of ethanol consumption and product distributions using a flow cell provided independent measurements of stoichiometry that were in reasonable agreement with values from Koutecky–Levich plots.