Photoelectrochemical study of TiO2inverse opalsElectronic supplementary information (ESI) available. See DOI: 10.1039/c1jm12674a.

The optical and photoelectrochemical behaviour of TiO2inverse opals and TiO2disordered macroporous structures has been investigated by means of UV-vis spectroscopy, cyclic voltammetry, chronopotentiometry and electrochemical impedance spectroscopy. These techniques, together with photonic band structure calculations, confirmed the better absorption of light of TiO2inverse opals, due to the slow light phenomenon, and indeed the status of metamaterials for such structures. TiO2inverse opals and TiO2disordered macroporous structures are shown to have the same recombination rate of photogenerated charge carriers, but TiO2inverse opals are characterized by a better reactivity towards O2which can also contribute to the improvement of the photocatalytic activity observed by several groups. [ABSTRACT FROM AUTHOR]