Fig. 1. (a) Electron transfer processes in TiO₂ functionalised with a molecular catalyst for H₂ production after UV-light excitation. The solid black and dashed red arrows indicate charge separation and recombination, respectively. Molecular structures of the catalysts for H⁺ reduction are shown in (b) for Co1, (c) for Co2 and (d) for Co3 (charges omitted for clarity). The blue arrows indicate the distance between the anchoring groups and the catalyst metal centre (r, Å), as determined by energy minimised DFT calculations (Fig. S1, ESI†).‡ .