Covalent ligation of Co molecular catalyst to carbon cloth for efficient electroreduction of CO2 in water

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Electrochemical reduction of CO2 to CO in water catalysed by porphyrins is a viable way to environmentally friendly CO2 valorisation, while efficient catalyst immobilization on the electrode surface is one of the key challenges to answer. Herein we present a concept of "molecular wire" i.e. connection of the catalyst to electrode via a conductive covalent linker. To covalently immobilize Co porphyrin core onto carbon cloth we employed reduction of corresponding diazonium salt. "Wiring' via resulting phenylene group had profound effect on electrocatalytic performance. Formation of CO in neutral aqueous electrolyte at –1.05 V vs NHE (η = 500 mV) occurs with TOF of 8.3 s−1 while noncovalent counterpart has TOF of 4.5 s−1 only. Compared to the noncovalent mode, covalent ligation leads to 2.4 times higher surface density of electrochemically active species and maximum FE (CO) is achieved at 50 mV less negative potential. The catalyst accumulated 3.9‧105 TON in 24 h long electrolysis surpassing performance of drop-cast analogue by a factor of 3 and showed FE (CO) of up to 81%. Notably, the TON and TOF values achieved in our study are one of the highest reported to date surpassing those measured for Fe hydroxyporphyrins and Co porphyrin-based covalent organic frameworks. Electrokinetic analysis demonstrated that the electron transfer from electrode onto porphyrin moiety plays an important role in overall reaction kinetics and conductive link with the support is a key element of heterogeneous catalyst design.

LanguageEnglish
Pages881-888
Number of pages8
JournalApplied Catalysis B: Environmental
Volume244
DOIs
Publication statusPublished - 5 May 2019

Fingerprint

porphyrin
Porphyrins
Carbon Monoxide
Carbon
catalyst
electrode
Catalysts
Water
carbon
Electrodes
water
reaction kinetics
Electric wiring
Electrolysis
Catalyst supports
Reaction kinetics
Chemical elements
immobilization
electrolyte
Electrolytes

Keywords

  • CO₂ electroreduction
  • Electrochemistry
  • Covalent immobilization
  • Cobalt porphyrin

Cite this

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title = "Covalent ligation of Co molecular catalyst to carbon cloth for efficient electroreduction of CO2 in water",
abstract = "Electrochemical reduction of CO2 to CO in water catalysed by porphyrins is a viable way to environmentally friendly CO2 valorisation, while efficient catalyst immobilization on the electrode surface is one of the key challenges to answer. Herein we present a concept of {"}molecular wire{"} i.e. connection of the catalyst to electrode via a conductive covalent linker. To covalently immobilize Co porphyrin core onto carbon cloth we employed reduction of corresponding diazonium salt. {"}Wiring' via resulting phenylene group had profound effect on electrocatalytic performance. Formation of CO in neutral aqueous electrolyte at –1.05 V vs NHE (η = 500 mV) occurs with TOF of 8.3 s−1 while noncovalent counterpart has TOF of 4.5 s−1 only. Compared to the noncovalent mode, covalent ligation leads to 2.4 times higher surface density of electrochemically active species and maximum FE (CO) is achieved at 50 mV less negative potential. The catalyst accumulated 3.9‧105 TON in 24 h long electrolysis surpassing performance of drop-cast analogue by a factor of 3 and showed FE (CO) of up to 81{\%}. Notably, the TON and TOF values achieved in our study are one of the highest reported to date surpassing those measured for Fe hydroxyporphyrins and Co porphyrin-based covalent organic frameworks. Electrokinetic analysis demonstrated that the electron transfer from electrode onto porphyrin moiety plays an important role in overall reaction kinetics and conductive link with the support is a key element of heterogeneous catalyst design.",
keywords = "CO₂ electroreduction, Electrochemistry, Covalent immobilization, Cobalt porphyrin",
author = "Marianov, {Aleksei N.} and Yijiao Jiang",
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Covalent ligation of Co molecular catalyst to carbon cloth for efficient electroreduction of CO2 in water. / Marianov, Aleksei N.; Jiang, Yijiao.

In: Applied Catalysis B: Environmental, Vol. 244, 05.05.2019, p. 881-888.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Covalent ligation of Co molecular catalyst to carbon cloth for efficient electroreduction of CO2 in water

AU - Marianov, Aleksei N.

AU - Jiang, Yijiao

PY - 2019/5/5

Y1 - 2019/5/5

N2 - Electrochemical reduction of CO2 to CO in water catalysed by porphyrins is a viable way to environmentally friendly CO2 valorisation, while efficient catalyst immobilization on the electrode surface is one of the key challenges to answer. Herein we present a concept of "molecular wire" i.e. connection of the catalyst to electrode via a conductive covalent linker. To covalently immobilize Co porphyrin core onto carbon cloth we employed reduction of corresponding diazonium salt. "Wiring' via resulting phenylene group had profound effect on electrocatalytic performance. Formation of CO in neutral aqueous electrolyte at –1.05 V vs NHE (η = 500 mV) occurs with TOF of 8.3 s−1 while noncovalent counterpart has TOF of 4.5 s−1 only. Compared to the noncovalent mode, covalent ligation leads to 2.4 times higher surface density of electrochemically active species and maximum FE (CO) is achieved at 50 mV less negative potential. The catalyst accumulated 3.9‧105 TON in 24 h long electrolysis surpassing performance of drop-cast analogue by a factor of 3 and showed FE (CO) of up to 81%. Notably, the TON and TOF values achieved in our study are one of the highest reported to date surpassing those measured for Fe hydroxyporphyrins and Co porphyrin-based covalent organic frameworks. Electrokinetic analysis demonstrated that the electron transfer from electrode onto porphyrin moiety plays an important role in overall reaction kinetics and conductive link with the support is a key element of heterogeneous catalyst design.

AB - Electrochemical reduction of CO2 to CO in water catalysed by porphyrins is a viable way to environmentally friendly CO2 valorisation, while efficient catalyst immobilization on the electrode surface is one of the key challenges to answer. Herein we present a concept of "molecular wire" i.e. connection of the catalyst to electrode via a conductive covalent linker. To covalently immobilize Co porphyrin core onto carbon cloth we employed reduction of corresponding diazonium salt. "Wiring' via resulting phenylene group had profound effect on electrocatalytic performance. Formation of CO in neutral aqueous electrolyte at –1.05 V vs NHE (η = 500 mV) occurs with TOF of 8.3 s−1 while noncovalent counterpart has TOF of 4.5 s−1 only. Compared to the noncovalent mode, covalent ligation leads to 2.4 times higher surface density of electrochemically active species and maximum FE (CO) is achieved at 50 mV less negative potential. The catalyst accumulated 3.9‧105 TON in 24 h long electrolysis surpassing performance of drop-cast analogue by a factor of 3 and showed FE (CO) of up to 81%. Notably, the TON and TOF values achieved in our study are one of the highest reported to date surpassing those measured for Fe hydroxyporphyrins and Co porphyrin-based covalent organic frameworks. Electrokinetic analysis demonstrated that the electron transfer from electrode onto porphyrin moiety plays an important role in overall reaction kinetics and conductive link with the support is a key element of heterogeneous catalyst design.

KW - CO₂ electroreduction

KW - Electrochemistry

KW - Covalent immobilization

KW - Cobalt porphyrin

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JO - Applied Catalysis B: Environmental

T2 - Applied Catalysis B: Environmental

JF - Applied Catalysis B: Environmental

SN - 0926-3373

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