Functional Role of Pyridinium during Aqueous Electrochemical Reduction of CO2 on Pt(111)

详细信息    查看全文

• 作者：Mehmed Z. Ertem ; Steven J. Konezny ; C. Moyses Araujo ; Victor S. Batista
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2013
• 出版时间：March 7, 2013
• 年：2013
• 卷：4
• 期：5
• 页码：745-748
• 全文大小：240K
• 年卷期：v.4,no.5(March 7, 2013)
• ISSN：1948-7185

文摘

Recent breakthroughs in electrochemical studies have reported aqueous CO₂ reduction to formic acid, formaldehyde, and methanol at low overpotentials (鈭?.58 V versus SCE), with a Pt working electrode in acidic pyridine (Pyr) solutions. We find that CO₂ is reduced by H atoms bound to the Pt surface that are transferred as hydrides to CO₂ in a proton-coupled hydride transfer (PCHT) mechanism activated by pyridinium (PyrH⁺), CO₂ + Pt鈥揌 + PyrH⁺ + e鈥?/sup> 鈫?Pyr + Pt + HCO₂H. The surface-bound H atoms consumed by CO₂ reduction is replenished by the one-electron reduction of PyrH⁺ through the proton-coupled electron transfer (PCET), PyrH⁺ + Pt + e鈥?/sup> 鈫?Pyr + Pt鈥揌. Pyridinium is essential to establish a high concentration of Br酶nsted acid in contact with CO₂ and with the Pt surface, much higher than the concentration of free protons. These findings are particularly relevant to generate fuels with a carbon-neutral footprint.

Keywords:

density functional theory (DFT); CO₂ reduction; electrocatalysis; pyridinium; proton-coupled hydride transfer (PCHT); proton-coupled electron transfer (PCET)