Copper(i) bis(diimine) sensitized titania nanotube array photoelectrodes for photoelectrochemical water oxidation†

Dye-sensitized photoelectrochemical cells (DS-PECs), devices inspired by photosynthesis, are being developed to advance the goal of using the sun as the sole source of energy for converting abundant resources to fuel and valuable chemicals. Herein, we report compact and vertically aligned titanium dioxide nanotubes grown through self-organized electrochemical anodization as semiconducting materials functionalized with a molecular copper(I) bis(diimine)-based acceptor–chromophore–donor to yield a photoanode capable of carrying out oxidative processes. The ability of these dye-sensitized photoanodes to drive oxidative processes is further confirmed photoelectrochemically through activation of a molecular iridium(III) water oxidation pre-catalyst where ultimately a Faradaic efficiency of 84% is found for O₂ production.