Molecularly dispersed nickel complexes on N-doped graphene for electrochemical CO<inf>2</inf> reduction
1
Issued Date
2023-01-01
Resource Type
ISSN
14779226
eISSN
14779234
Scopus ID
2-s2.0-85162196579
Journal Title
Dalton Transactions
Rights Holder(s)
SCOPUS
Bibliographic Citation
Dalton Transactions (2023)
Suggested Citation
Juthathan M., Chantarojsiri T., Chainok K., Butburee T., Thamyongkit P., Tuntulani T., Leeladee P. Molecularly dispersed nickel complexes on N-doped graphene for electrochemical CO<inf>2</inf> reduction. Dalton Transactions (2023). doi:10.1039/d3dt00878a Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/87688
Title
Molecularly dispersed nickel complexes on N-doped graphene for electrochemical CO<inf>2</inf> reduction
Other Contributor(s)
Abstract
In this work, new hybrid catalysts based on molecularly dispersed nickel complexes on N-doped graphene were developed for electrochemical CO2 reduction (ECR). Nickel(ii) complexes (1-Ni, 2-Ni), and a new crystal structure ([2-Ni]Me), featuring N4-Schiff base macrocycles, were synthesized and investigated for their potential in ECR. Cyclic voltammetry (CV) in NBu4PF6/CH3CN solution demonstrated that the nickel complexes bearing N-H groups (1-Ni and 2-Ni) showed a substantial current enhancement in the presence of CO2, while the absence of N-H groups ([2-Ni]Me) resulted in an almost unchanged voltammogram. This indicated the necessity of the N-H functionality towards ECR in aprotic media. All three nickel complexes were successfully immobilized on nitrogen-doped graphene (NG) via non-covalent interactions. All three Ni@NG catalysts exhibited satisfactory CO2-to-CO reduction in aqueous NaHCO3 solution with the faradaic efficiency (FE) of 60-80% at the overpotential of 0.56 V vs. RHE. The ECR activity of [2-Ni]Me@NG also suggested that the N-H moiety from the ligand is less important in the heterogeneous aqueous system owing to viable hydrogen-bond formation and proton donors from water and bicarbonate ions. This finding could pave the way for understanding the effects of modifying the ligand framework at the N-H position toward fine tuning the reactivity of hybrid catalysts through molecular-level modulation.