Electrocatalytic reduction of CO2 using the dinuclear rhenium(I) complex [ReCl(CO)3(μ-tptzH)Re(CO)3

Abstract

The dinuclear rhenium(I) complex [ReCl(CO)3(μ-tptzH)Re(CO)3] (where tptz-H is 2,4,6-tri(pyridine-2-yl)-2H-1,3,5-triazine-1-ide) was used as an electrocatalyst for the homogeneous and heterogeneous reduction of CO2. The electrochemical behavior of the complex in solution and at the surface of an electrode after its adsorption was studied for the reduction of CO2 on a carboxylated multiwall carbon nanotubes modified (CMWCNTs) pencil graphite electrode (PGE) using cyclic voltammetric methods. The reduction potential of CO2 in homogenous studies was −853mV versus NHE in acetonitrile. The results show that methanol (MeOH) as a weak Brönsted acid enhances the rate of the catalytic process for the reduction of CO2 in acetonitrile. Under heterogonous conditions, the dinuclear complex was only casted on the CMWCNTs–PGE and investigated in an acidic solution of MeOH. In comparison with the homogeneous catalyst, the heterogeneous catalyst shows a higher cathodic current and a lower over potential (about 650mV).