A robust ruthenium complex with nonyl-substituted bpy ligand for dye-sensitized photoelectrochemical cell application

Abstract

Stability, electrochemical and photoelectrochemical studies of a new ruthenium polypyridyl complex [Ru(nbipy)2(bipydipa)]2+ (P2), where nbipy = 4,4′-dinonyl-2,2′-bipyridine and bipydipa = 2,2′-bipyridine-4,4′-diphosphonic acid, immobilised as FTO/TiO2/P2 electrode were investigated and compared with the parent complex [Ru(bipy)2(bipydipa)]2+ (P1), where bipy = 2,2′-bipyridine. Upon immersion in pH 5.9 and pH 8.1 solutions, P2 absorbed in TiO2 proved to be less prone to desorption from the surface in comparison with P1. The immobilised P2 in FTO/TiO2/P2 electrode displays higher RuIII/RuII oxidation potential (1.47 V vs. NHE) than that of the P1 counterpart (1.33 V vs. NHE). The DSPEC assembled with FTO/TiO2/P2 electrode shows greater photocurrent densities, higher amount of hydrogen gas, better Faradaic efficiency and greater photostability during the photolysis experiments at 0.2 V NHE.