Passivated dye-sensitised TiO2 photoanode with conductive polymer with improved photocatalyst stability for photoelectrochemical application

A protective conductive polymer electrolyte (PE) composed of poly(vinylidenefluoride-co-hexafluoropropylene), 49% poly(methylmethacrylate)-grafted natural rubber and lithium tetrafluoroborate (PVdF-HFP-MG49-LiBF4, also referred as PHMLi) was used as a strategic method to improve the photocatalyst stability of the dye sensitiser on a TiO2 photoanode. PHMLi was fabricated onto a ruthenium dye-sensitised TiO2 photoanode (FTO/TiO2/Ru/PHMLi) using a dip-coating technique. The COOH anchoring groups in the ruthenium dye are known to undergo hydrolysis in photoelectrochemical cell (PEC) in a direct water-splitting reaction causing the ruthenium dye to desorb from the TiO2 photoanode. Thus, PHMLi was applied to sustain the physical, chemical and photostability properties of the ruthenium dye. The PEC properties of FTO/TiO2/Ru/PHMLi were investigated using a 0.5 M KOH electrolyte. The result indicated that PHMLi protective layer exhibited the ability to retain the ruthenium dye sensitiser on the TiO2 surface and improved the overall photocatalyst stability of the PEC photoanode.