Electrochemical mass spectrometry study of the pyridine/pyridinium in the CO2 electroreduction reaction on copper electrodes

Author(s)

Messias, Igor ; Pinto, Maria R. ; Roveda, Antonio C. ; Queiroz, Adriana C. ; Lima, Fabio H. B. ; Nagao, Raphael

• Document type: Journal article
• Source: Electrochimica Acta; v. 436, p. 8-pg., 2022-11-02.

Abstract

The role of pyridine and its protonated form, pyridinium, in the CO2 Electroreduction Reaction (CO2ER) is a long -discussed subject, with controversies concerning whether pyridinium act as a catalyst or is merely participating as a proton source for hydrogen evolution reaction. The pyridine electroactivity is often discussed in terms of faradaic currents from cyclic voltammetry, in which the catalytic effect of pyridine is characterized by a well-defined cathodic current peak. The analysis is not straightforward, and a deeper look is especially needed when dealing with complex systems such as CO2ER. To get further insight, we examine the electrochemical behavior of the pyridine/pyridinium pair with the aid of online mass spectrometry coupled to an electrochemical cell (EC-MS) on a polycrystalline copper electrode. Copper is a unique metal, capable to generate a variety of volatile hydrocarbons such as methane and ethylene during CO2ER. For this reason, this metal was selected to investigate the CO2ER in the presence and absence of pyridine by monitoring the mass fragments of H2 (m/z = 2), CH4 (m/z = 15), C2H4 (m/z = 26) and pyridine (m/z = 26, 52 and 79). Our findings validate the discussion of pyridine promoting the formation of dihydrogen (H2) via pyridinium deprotonation, as evidenced by ionic currents signals of both H2 and pyridine. Furthermore, clear evidence of pyridine enhancing CO2ER was not detected in the formation of any measurable product. (AU)

• FAPESP's process: 14/50279-4 - Brasil Research Centre for Gas Innovation
• Grantee: Julio Romano Meneghini
• Support Opportunities: Research Grants - Research Centers in Engineering Program
• FAPESP's process: 17/11986-5 - Generation and storage of New Energy: bringing technological development for the country
• Grantee: Ana Flávia Nogueira
• Support Opportunities: Research Grants - Research Centers in Engineering Program
• FAPESP's process: 19/22183-6 - Electrocatalysis VI: fundamental and applied aspects of emerging and classical problems in electrochemical energy conversion
• Grantee: Edson Antonio Ticianelli
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 16/13323-0 - Carbon Dioxide and Water Electrochemistry: Application in Energy Conversion and Storage
• Grantee: Fabio Henrique Barros de Lima
• Support Opportunities: Regular Research Grants
• FAPESP's process: 21/08868-6 - Tandem dissipative electrodes applied in the reduction of carbon dioxide to the formation of C2+ products
• Grantee: Raphael Nagao de Sousa
• Support Opportunities: Program for Research on Bioenergy (BIOEN) - Regular Program Grants
• FAPESP's process: 19/08244-2 - Synthesis of nanowires for application in the reduction reaction of carbon dioxide
• Grantee: Maria Rodrigues Pinto
• Support Opportunities: Scholarships in Brazil - Doctorate