Innovative three-dimensional (3D) eco-TiO(2) photocatalysts for practical environmental and bio-medical applications

It is known that water purified by conventional TiO(2) photocatalysts may not be safe enough for drinking, due to the toxicity by tiny existence of TiO(2) nanoparticles after water treatment. We herein demonstrate a facile design of a three-dimensional (3D) TiO(2) photocatalyst structure with which both the efficiency of purification and the safety level of the final purified water can be improved and ensured, respectively. The structure, consisting of 3D sulfur-doped TiO(2) microtubes in nanotubes (eco-TiO(2)), is suitable for both environmental and bio-medical applications. Investigation of its formation mechanism reveals that anodic aluminum oxide (AAO), owing to a spatial constraint, causes a simple, nanoparticles-to-nanotubes structural rearrangement as a template for nanotube growth. It is found that eco-TiO(2) can be activated under visible-light irradiation by non-metal (sulfur; S) doping, after which it shows visible-light photocatalytic activities over a range of solar energy. Importantly, an in vitro cytotoxicity test of well-purified water by eco-TiO(2) confirms that eco-TiO(2) satisfies the key human safety conditions.