Experimental reasons for the variable efficiencies of organic electrocatalysts used for converting carbon dioxide to methanol

Pyridinium (the protonated form of pyridine) and related compounds have been proposed to be promising homogenous electrocatalysts in the electrochemical reduction of CO2 to methanol due to the low overpotential required to achieve faradaic yields of about 20 %, although the percentage yields vary dr...

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Main Authors: Budanovic, Maja, Urbančok, Dejan, Er, Jasmine Y. H., Tessensohn, Malcolm Eugene, Webster, Richard David
Other Authors: School of Physical and Mathematical Sciences
Format: Article
Language:English
Published: 2022
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Online Access:https://hdl.handle.net/10356/159908
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Institution: Nanyang Technological University
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spelling sg-ntu-dr.10356-1599082022-07-22T07:49:05Z Experimental reasons for the variable efficiencies of organic electrocatalysts used for converting carbon dioxide to methanol Budanovic, Maja Urbančok, Dejan Er, Jasmine Y. H. Tessensohn, Malcolm Eugene Webster, Richard David School of Physical and Mathematical Sciences Nanyang Environment and Water Research Institute Environmental Chemistry and Materials Centre Science::Chemistry Controlled Potential Electrolysis Gas Chromatography Pyridinium (the protonated form of pyridine) and related compounds have been proposed to be promising homogenous electrocatalysts in the electrochemical reduction of CO2 to methanol due to the low overpotential required to achieve faradaic yields of about 20 %, although the percentage yields vary dramatically between different research groups. In this study, experimental conditions were varied during the electrolysis of CO2 at a platinum electrode in the presence of pyridinium to determine the reasons for the discrepancies in the yields of methanol reported between different research groups. Two other vitamin-based and environmentally friendly nitrogen-containing heterocyclic compounds (nicotinamide and nicotinic acid) which have structural similarities to the promising but toxic pyridine homogeneous electrocatalyst, were also investigated as alternative electrocatalysts for the reduction of CO2 in aqueous acidic media. Cyclic voltammetry studies suggest that nicotinamide and nicotinic acid (forms of vitamin B3) follow a similar reaction mechanism as pyridine in the reduction of CO2. Relatively low faradaic yields of methanol were obtained during controlled potential electrolysis experiments for all the electrocatalysts (0.4–1.9 %) which can be attributed to the low solubility of CO2 along with the competing hydrogen evolution reaction. It was found that adventitious sources of methanol were responsible for greatly inflating the apparent yields of methanol unless scrupulous care was taken in controlling the experimental conditions. The problem with background methanol is particularly difficult to control due to the electrochemical reactions typically generating products in the parts per million range, considerably lower than normal synthetic reactions. Ministry of Education (MOE) National Research Foundation (NRF) The authors are grateful to the National Research Foundation (NRF) Singapore under its Campus for Research Excellence and Technological Enterprise (CREATE) program and the Singapore Government MOE Academic Research Fund Tier 1 Grant (RG3/19) for funding. 2022-07-05T07:04:16Z 2022-07-05T07:04:16Z 2021 Journal Article Budanovic, M., Urbančok, D., Er, J. Y. H., Tessensohn, M. E. & Webster, R. D. (2021). Experimental reasons for the variable efficiencies of organic electrocatalysts used for converting carbon dioxide to methanol. ChemElectroChem, 8(11), 2075-2086. https://dx.doi.org/10.1002/celc.202100335 2196-0216 https://hdl.handle.net/10356/159908 10.1002/celc.202100335 2-s2.0-85108562961 11 8 2075 2086 en RG3/19 ChemElectroChem © 2021 Wiley-VCH GmbH. All rights reserved.
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Science::Chemistry
Controlled Potential Electrolysis
Gas Chromatography
spellingShingle Science::Chemistry
Controlled Potential Electrolysis
Gas Chromatography
Budanovic, Maja
Urbančok, Dejan
Er, Jasmine Y. H.
Tessensohn, Malcolm Eugene
Webster, Richard David
Experimental reasons for the variable efficiencies of organic electrocatalysts used for converting carbon dioxide to methanol
description Pyridinium (the protonated form of pyridine) and related compounds have been proposed to be promising homogenous electrocatalysts in the electrochemical reduction of CO2 to methanol due to the low overpotential required to achieve faradaic yields of about 20 %, although the percentage yields vary dramatically between different research groups. In this study, experimental conditions were varied during the electrolysis of CO2 at a platinum electrode in the presence of pyridinium to determine the reasons for the discrepancies in the yields of methanol reported between different research groups. Two other vitamin-based and environmentally friendly nitrogen-containing heterocyclic compounds (nicotinamide and nicotinic acid) which have structural similarities to the promising but toxic pyridine homogeneous electrocatalyst, were also investigated as alternative electrocatalysts for the reduction of CO2 in aqueous acidic media. Cyclic voltammetry studies suggest that nicotinamide and nicotinic acid (forms of vitamin B3) follow a similar reaction mechanism as pyridine in the reduction of CO2. Relatively low faradaic yields of methanol were obtained during controlled potential electrolysis experiments for all the electrocatalysts (0.4–1.9 %) which can be attributed to the low solubility of CO2 along with the competing hydrogen evolution reaction. It was found that adventitious sources of methanol were responsible for greatly inflating the apparent yields of methanol unless scrupulous care was taken in controlling the experimental conditions. The problem with background methanol is particularly difficult to control due to the electrochemical reactions typically generating products in the parts per million range, considerably lower than normal synthetic reactions.
author2 School of Physical and Mathematical Sciences
author_facet School of Physical and Mathematical Sciences
Budanovic, Maja
Urbančok, Dejan
Er, Jasmine Y. H.
Tessensohn, Malcolm Eugene
Webster, Richard David
format Article
author Budanovic, Maja
Urbančok, Dejan
Er, Jasmine Y. H.
Tessensohn, Malcolm Eugene
Webster, Richard David
author_sort Budanovic, Maja
title Experimental reasons for the variable efficiencies of organic electrocatalysts used for converting carbon dioxide to methanol
title_short Experimental reasons for the variable efficiencies of organic electrocatalysts used for converting carbon dioxide to methanol
title_full Experimental reasons for the variable efficiencies of organic electrocatalysts used for converting carbon dioxide to methanol
title_fullStr Experimental reasons for the variable efficiencies of organic electrocatalysts used for converting carbon dioxide to methanol
title_full_unstemmed Experimental reasons for the variable efficiencies of organic electrocatalysts used for converting carbon dioxide to methanol
title_sort experimental reasons for the variable efficiencies of organic electrocatalysts used for converting carbon dioxide to methanol
publishDate 2022
url https://hdl.handle.net/10356/159908
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