Hydrogen production by Tuning the Photonic Band Gap with the Electronic Band Gap of TiO₂

Tuning the photonic band gap (PBG) to the electronic band gap (EBG) of Au/TiO₂ catalysts resulted in considerable enhancement of the photocatalytic water splitting to hydrogen under direct sunlight. Au/TiO₂ (PBG-357 nm) photocatalyst exhibited superior photocatalytic performance under both UV and sunlight compared to the Au/TiO₂ (PBG-585 nm) photocatalyst and both are higher than Au/TiO₂ without the 3 dimensionally ordered macro-porous structure materials. The very high photocatalytic activity is attributed to suppression of a fraction of electron-hole recombination route due to the co-incidence of the PBG with the EBG of TiO₂ These materials that maintain their activity with very small amount of sacrificial agents (down to 0.5 vol.% of ethanol) are poised to find direct applications because of their high activity, low cost of the process, simplicity and stability.