Dye sensitized solar cells were fabricated with free standing TiO2 nanotube (TNT) array films, which were prepared by template assisted atomic layer deposition (ALD) with precise wall thickness control. Efforts to improve the photovoltaic performance were made by using Al2O3 barrier layer coating in conjunction with TiCl4 surface modification. An Al2O3 thin layer was deposited on the TNT electrode by ALD to serve as the charge recombination barrier, but it suffers from the drawback of decreasing the photoelectron injection from dye into TiO2 when the barrier layer became too thick. With the TiCl4 treatment in combination with optimal thickness coating, this problem could be avoided. The co-surface treated electrode presents superior surface property with low recombination rate and good electron transport property. A high conversion efficiency of 8.62% is obtained, which is about 1.8 times that of the device without surface modifications.

A new photocatalyst was developed by coupling threedimensionally ordered macroporous (3DOM) TiO 2 with platinum (Pt) and reduced graphene oxide (rGO) for water purification applications under visible light. The rGO/Pt/3DOM TiO 2 ternary photocatalyst was synthesized by codecoration of 3DOM TiO 2 prepared by the colloidal crystal templating approach with Pt nanoparticles and rGO nanosheets via impregnation and in situ reduction methods. Modification with Pt and rGO reduced the band energy and significantly improved the visible light absorption of the rGO/Pt/3DOM TiO 2 photocatalyst. The performance of rGO/Pt/3DOM TiO 2 was investigated for the photodegradation of methyl orange as a model dye pollutant in water under visible light irradiation. rGO/Pt/3DOM TiO 2 enhanced the degradation rates of methyl orange by a factor of 6, 4, and 2 compared to bare 3DOM TiO 2 , Pt/3DOM TiO 2 , and rGO/3DOM TiO 2 , respectively. The significantly enhanced photocatalytic activity of rGO/Pt/3DOM TiO 2 may be attributed to the synergy of the highly ordered 3DOM structure that induced the slow photon effect and the decorated Pt and rGO that promoted light absorption and charge separation. The rGO/Pt/3DOM TiO 2 ternary photocatalyst showed high stability and can be used for several cycles without reducing activity. Results suggested that rGO/Pt/3DOM may hold promises as a visible light photocatalyst for the removal of waterborne contaminants.

The influence of water quality and elucidation of the removal mechanism of estrogenic compounds removal electrocoagulation.

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