Electrocatalytic carbon dioxide activation: the rate-determining step of pyridinium-catalyzed CO2 reduction

ChemSusChem. 2011 Feb 18;4(2):191-6. doi: 10.1002/cssc.201000379.

Abstract

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).

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Algorithms
  • Carbon Dioxide / chemistry*
  • Catalysis
  • Electrochemistry
  • Electrodes
  • Energy Transfer
  • Hydrogen / chemistry
  • Hydrogen-Ion Concentration
  • Kinetics
  • Nitrogen / chemistry
  • Oxidation-Reduction
  • Pyridines / chemistry*
  • Semiconductors
  • Temperature

Substances

  • Pyridines
  • Carbon Dioxide
  • Hydrogen
  • Nitrogen