Efficiency enhancement of the electrocatalytic reduction of CO 2: fac-[Re(v-bpy)(CO) 3Cl] electropolymerized onto mesoporous TiO 2 electrodes

Abstract

As the greenhouse effect increases, the development of systems able to convert with high efficiency CO 2 to energetically rich molecules owns a crucial weight in the technological and environmental domain. As catalyst, rhenium complexes, of the type fac-[Re(L)(CO) 3Cl] (i.e. L = 2,2′-bipyridyl or 4,4′-bipyridyl), have attracted a large interest demonstrating promising catalytic properties. fac-[Re(v-bpy)(CO) 3Cl]-based polymer deposited onto a solid support has been already investigated as heterogeneous catalyst in the reduction of CO 2. Here, we deposited by electrochemical polymerization fac-[Re(v-bpy)(CO) 3Cl] onto a nanocrystalline TiO 2 film on glass and we investigated by cyclic voltammetry the properties of such heterogeneous catalyst in the electrochemical reduction of CO 2. We demonstrated that the nanoporous nature of the substrate allows to increase the two-dimensional number of redox sites per surface area and hence to get a significant enhancement of the catalytic yield.