title: Electrocatalytic carbon dioxide activation: the rate-determining step of pyridinium-catalyzed CO2 reduction.
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).
authors.affiliation: Department of Chemistry, Princeton University, Princeton, NJ 08536, USA.
authors.forename: Amanda J
authors.initials: AJ
authors.lastname: Morris
authors.forename: Robert T
authors.initials: RT
authors.lastname: McGibbon
authors.forename: Andrew B
authors.initials: AB
authors.lastname: Bocarsly
mesh_terms: D000465:Algorithms; D002245:Carbon Dioxide / Q000737:chemistry*; D002384:Catalysis; D004563:Electrochemistry; D004566:Electrodes; D004735:Energy Transfer; D006859:Hydrogen / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009584:Nitrogen / Q000737:chemistry; D010084:Oxidation-Reduction; D011725:Pyridines / Q000737:chemistry*; D012666:Semiconductors; D013696:Temperature
chemical_list: D011725:Pyridines; D002245:Carbon Dioxide; D006859:Hydrogen; D009584:Nitrogen