ELECTROCHEMICAL CO2 REDUCTION OF RHENIUM TRICARBONYL COMPLEX

Abstract

Carbon dioxide is considered as a primary reason for global climate change, thus CO2 needs to be urgently reduced. Catalytic conversion of CO2 into chemical fuels is one of the most crucial technologies that can address both global warming and the depletion of fossil fuels. Rhenium tricarbonyl complex [Re(bpy)(CO)3Cl] (bpy: 2,2’ bipyridine) possesses a great potential of capturing and highly selective converting CO2 to carbon monoxide. In the current study, we synthesized and characterized the structure of [Re(bpy)(CO)3Cl] by 1H NMR, ESI-MS, FITR, and PL spectroscopy. The electrochemical properties and the electrochemical CO2 reduction of [Re(bpy)(CO)3Cl] in the absence and presence of an electron donor source were carried out using cyclic voltammetric measurements. The cyclic voltammogram of [Re(bpy)(CO)3Cl] in N2-saturated DMF solution displayed one irreversible reduction wave at -1.33 V. [Re(bpy)(CO)3Cl] expressed its electrocatalytic behavior in CO2 atmosphere by the enhancement of the cathodic current density. The current increased approximately twofold in CO2-saturated DMF solution (from 0.15 to 0.32 mA/cm2) and more enhancement when adding TEOA solvent. With the presence of an electron donor, the CO2 reduction efficiency of [Re(bpy)(CO)3Cl] was improved and represented by an approximately fourfold increase in cathodic current from 0.32 to 1.12 mA/cm2. One-electron reduced species of [Re(bpy)(CO)3Cl] observed at 1.33 V in N2 and CO2-saturated electrolytes contributed to the reaction with CO2.