Mn(III) Catalyzed Electrochemical Reduction of CO2 on Carbon Electrodes

Khalaf M Alenezi

doi:10.5562/cca3614

Abstract

Though challenging, conversion of carbon dioxide (CO2) to valuable products is an emerging area of research. Electrochemical reduction (ECR) has emerged as an efficient and rapid technique to achieve this goal. Herein, 5,10,15,20-tetraphenyl-21H, 23H-porphine manganese(III) chloride [(Mn(TPP)Cl)] catalyzed CO2 reduction at vitreous carbon electrode in acetonitrile electrolyte is reported. The effect of catalyst concentration, addition of Brönsted acid (CF3CH2OH) to CO2-saturated solution have been studied and reported. Based on the results, possible mechanistic pathways have also been suggested and discussed.

Highlights

F OLLOWING the first industrial revolution, a significant amount of carbon dioxide (CO2) has already been emitted to the atmosphere leading to global warming, icecaps melting, ocean acidification and other fates.[1,2] This issue, along with rapid increase human population, is a matter of serious concern, especially when the level of non-renewable energies is constantly declining
It has been demonstrated that a minor variation of the ligand core or change in the metal center has a significant effect on overpotential, Faradaic efficiency (FE), turn over frequency (TOF), turnover number (TON) and selectivity of the products.[17]
The cyclic voltammogram (CV) of Mn(TPP)Cl recorded in 0.1 M [Bu4N][BF4]-MeCN under Ar (Figure 2) displayed two redox pairs (–0.15 V and –1.3 V vs Ag/AgCl)

Summary

Introduction

F OLLOWING the first industrial revolution, a significant amount of carbon dioxide (CO2) has already been emitted to the atmosphere leading to global warming, icecaps melting, ocean acidification and other fates.[1,2] This issue, along with rapid increase human population, is a matter of serious concern, especially when the level of non-renewable energies is constantly declining. The study was carried out using Mn(TPP)Cl complex (Figure 1) at vitreous carbon electrode in the acetonitrile (MeCN) electrolyte and the results of the findings are discussed . From the CV, it is clear that CO2 interacted with the reduced catalyst [Mn(I)] at the second reduction wave (–1.3 V vs Ag/AgCl) of Mn(TPP)Cl as evident from an increase in peak current (IIIip).

Results

Conclusion