TY - JOUR
T1 - Electrochemistry of aqueous pyridinium
T2 - Exploration of a key aspect of electrocatalytic reduction of CO2 to methanol
AU - Yan, Yong
AU - Zeitler, Elizabeth L.
AU - Gu, Jing
AU - Hu, Yuan
AU - Bocarsly, Andrew Bruce
PY - 2013/9/25
Y1 - 2013/9/25
N2 - 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.
AB - 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.
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U2 - 10.1021/ja4064052
DO - 10.1021/ja4064052
M3 - Article
C2 - 23972003
AN - SCOPUS:84884835001
SN - 0002-7863
VL - 135
SP - 14020
EP - 14023
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 38
ER -