TY - JOUR
T1 - Heterogeneous carbon dioxide reduction reaction by cobalt complexes of 4′,4′′′-disubstituted derivatives of quinquepyridine immobilized on carbon black
AU - Reddu, Vikas
AU - Sun, Libo
AU - Duo, Shuo
AU - Chen, Xinqi
AU - Wu, Tian
AU - Dai, Wei
AU - Wang, Xin
PY - 2021/6/1
Y1 - 2021/6/1
N2 - Molecular catalysts represent an excellent class of materials for carbon dioxide reduction that can perform with superior selectivity and allow for the molecular-level tuning of their structure-performance relationship. In this study, three quinquepyridine-based cobalt complexes were synthesized with different types of functional group (-N(CH3)2, -NO2, -H) substitutions allowing us to manipulate the electronic field around the metal center due to their varying electron donating and withdrawing tendencies. These were heterogenized onto carbon black enabling them to perform in near neutral aqueous conditions (pH = 6.8). At an optimized catalyst loading of ~100 μ g cm−2, dimethylamine- and nitro-substituted complexes outperformed the unsubstituted complex, wherein, dimethylamine substituted complex attained nearly 100% faradaic efficiency towards CO formation at a low overpotential (η) of 0.59 V (-0.7 V vs. RHE) and achieved a current density (j) of ~4.3 mA cm−2. It maintained its robust performance towards the formation of CO over a wide range of overpotential while suppressing the competitive hydrogen evolution reaction. This enhanced activity compared to the unsubstituted complex was attributed to the effects exerted by the functional groups at the molecular level. © 2021 Elsevier Ltd
AB - Molecular catalysts represent an excellent class of materials for carbon dioxide reduction that can perform with superior selectivity and allow for the molecular-level tuning of their structure-performance relationship. In this study, three quinquepyridine-based cobalt complexes were synthesized with different types of functional group (-N(CH3)2, -NO2, -H) substitutions allowing us to manipulate the electronic field around the metal center due to their varying electron donating and withdrawing tendencies. These were heterogenized onto carbon black enabling them to perform in near neutral aqueous conditions (pH = 6.8). At an optimized catalyst loading of ~100 μ g cm−2, dimethylamine- and nitro-substituted complexes outperformed the unsubstituted complex, wherein, dimethylamine substituted complex attained nearly 100% faradaic efficiency towards CO formation at a low overpotential (η) of 0.59 V (-0.7 V vs. RHE) and achieved a current density (j) of ~4.3 mA cm−2. It maintained its robust performance towards the formation of CO over a wide range of overpotential while suppressing the competitive hydrogen evolution reaction. This enhanced activity compared to the unsubstituted complex was attributed to the effects exerted by the functional groups at the molecular level. © 2021 Elsevier Ltd
KW - Carbon dioxide reduction
KW - Cobalt complexes
KW - Disubstituted quinquepyridine derivatives
KW - Heterogeneous molecular catalysis
KW - Non-covalent immobilization
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U2 - 10.1016/j.electacta.2021.138224
DO - 10.1016/j.electacta.2021.138224
M3 - RGC 21 - Publication in refereed journal
SN - 0013-4686
VL - 380
JO - Electrochimica Acta
JF - Electrochimica Acta
M1 - 138224
ER -
