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Electrocatalytic Carbon Dioxide Activation: The Rate‐Determining Step of Pyridinium‐Catalyzed CO 2 Reduction
Author(s) -
Morris Amanda J.,
McGibbon Robert T.,
Bocarsly Andrew B.
Publication year - 2011
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201000379
Subject(s) - pyridinium , chemistry , catalysis , inorganic chemistry , cyclic voltammetry , electrochemistry , reaction rate constant , platinum , reactivity (psychology) , arrhenius equation , electrocatalyst , rate determining step , reaction rate , activation energy , electrode , organic chemistry , kinetics , medicine , physics , alternative medicine , quantum mechanics , pathology
The reactivity of reduced pyridinium with CO 2 was investigated as a function of catalyst concentration, temperature, and pressure at platinum electrodes. Concentration experiments show that the catalytic current measured by cyclic voltammetry increases linearly with pyridinium and CO 2 concentrations; this indicates that the rate‐determining step is first order in both. The formation of a carbamate intermediate is supported by the data presented. Increased electron density at the pyridyl nitrogen upon reduction, as calculated by DFT, favors a Lewis acid/base interaction between the nitrogen and the CO 2 . The rate of the known side reaction, pyridinium coupling to form hydrogen, does not vary over the temperature range investigated and had a rate constant of 2.5 M −1 s −1 . CO 2 reduction followed Arrhenius behavior and the activation energy determined by electrochemical simulation was (69±10) kJ mol −1 .