Oxidative electropolymerization films of a styrene-appending ruthenium complex with highly performed electrochemical, solar photoelectric conversion and photoelectrochemical oxygen reduction properties

Abstract

Vinyl or styrene-containing ruthenium complexes were previously reported to be reductively electropolymerized, which needed to be carried out under strict deoxygenation conditions. Here, we present the first example of an oxidatively electropolymerized thin film of a styrenyl-containing ruthenium complex, Ru1 under ambient condition. As revealed by UV–visible absorption spectroscopy, emission spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, electrochemical impedance spectroscopy, cyclic voltammetry, and photoelectrochemical measurements, the electropolymerized films, poly(Ru1)n, exhibited good adherence and chemical stability, porous structure, strong photoluminescence, well reversible and surface-controlled RuIII/II redox behavior. More interestingly, at a -0.4 V external bias potential, a significant cathodic photocurrent density of 8.04 μA/cm2 was observed for poly(Ru1)3-modified ITO electrode irradiated by 100 mW•cm−2 white light in an air-equilibrated 0.1 M Na2SO4 aqueous solution. Furthermore, the photo-current polarity could be switched from cathodic to anodic up to a photocurrent density of 9.22 μA/cm2 for poly(Ru1)3-modified ITO electrode as the electron donor of quinhydrone was added under external bias potential-free conditions. More interestingly, poly(Ru1)3 exhibited impressively strong photoelectrochemical oxygen reduction properties with a O2-induced 4.7-fold cathodic photo-current enhancement relative to a N2-saturated electrolyte solution condition. This work offers an efficient way to fabricate highly stabilized Ru(II) complex-based modified electrodes by facile oxidative electropolymerization of the styrenyl-containing ruthenium complex, offering poly(Ru1) films with intriguing applications in electrochemical, photoluminescence, photoelectrochemical O2 reduction and solar photoelectric conversion, molecular switching devices.