Visible light photocatalysts (Fe, N):TiO2 from ammonothermally processed, solvothermal self-assembly derived Fe-TiO2 mesoporous microspheres

Iron (III) and nitrogen co-doped mesoporous TiO 2 microspheres (Fe-N-TiO 2 ) are prepared using a self-assembly based solvothermal process followed by an ammonothermal method. Among all samples, 1 mol.% of Fe dopants and 500 °C nitridation (for 2 h) gives the highest visible light photoactivity. Results imply that the Fe 3+ /Fe 2+ dopant trap energy level introduced within the band gap in mildly Fe (∼1 at%) doped TiO 2 and the mesoporous nature of the material, both aid in the observed catalytic performance. Subjecting Fe-TiO 2 samples to ammonothermal process induces oxygen vancancies, and substitutional and interstitial N. This reduces optical band gap, and introduces local states. The lower band gap and local states together aid in the absorption of visible light and separation of charge carriers. Co-dopants are distributed uniformly in the best photocatalysts . The active species generated in the photocatalytic system is shown to be singlet molecular oxygen ( 1 O 2 ) using selective radical quenchers.