Growth and electrochemical behaviour of a poly [tricarbonyl(vinylbipyridyl)rhenium chloride] film. Heterogeneous reduction of CO2

Abstract

The mechanism of anionic electropolymerisation of [(vbpy)Re(CO)₃Cl], where vbpy is 4-vinyl-4′-methyl-2,2′-bipyridyl, has been studied with ellipsometry, and the nature of the film formed established. The chemical transformations of this film on reduction to – 1.9 V have been studied by in situ FTIR spectroscopy in the presence and absence of CO₂, and the spectra assigned using Timney's ligand effect parameters. This analysis shows that the reduction chemistry is somewhat simplified as compared to the homogeneous case studied earlier, with dimerisation of the reduction products much less prevalent. The films are highly active for CO₂ reduction but show long-term degradation, and one possible mechanism for this is explored with a combination of ellipsometry and FTIR.