Figure 5: Electron transfer paths in dye-sensitized TiO2. 1: dye (S) excitation; 2: electron injection from the excited dye to TiO2 conduction band (CB); 3: electron entrapment into Pt particles; 4: H+ reduction and H2 evolution over the metallic site; 5: regeneration of the oxidized dye by an electron donor (D); 6: electron recombination in the oxidized dye. Readapted from [1].