title: Electrochemistry of aqueous pyridinium: exploration of a key aspect of electrocatalytic reduction of CO2 to methanol.
abstract: The mechanism by which pyridinium (pyrH(+)) is reduced at a Pt electrode is a matter of recent controversy. The quasireversible cyclic voltammetric wave observed at -0.58 V vs SCE at a Pt electrode was originally proposed to correspond to reduction of pyrH(+) to pyridinyl radical (pyrH(•)). This mechanistic explanation for the observed electrochemistry seems unlikely in light of recent quantum mechanical calculations that predict a very negative reduction potential (-1.37 V vs SCE) for the formation of pyrH(•). Several other mechanisms have been proposed to account for the discrepancy in calculated and observed reduction potentials, including surface adsorption of pyrH(•), reduction of pyrH(+) by two electrons rather than one, and reduction of the pyrH(+) proton to a surface hydride rather than a π-based radical product. This final mechanism, which can be described as inner-sphere reduction of pyrH(+) to form a surface hydride, is consistent with experimental observations.
authors: Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States.
authors: Yong
authors: Y
authors: Yan
authors: Elizabeth L
authors: EL
authors: Zeitler
authors: Jing
authors: J
authors: Gu
authors: Yuan
authors: Y
authors: Hu
authors: Andrew B
authors: AB
authors: Bocarsly