Design and tuning functionality of rod-like titanium dioxide-nickel oxide composites via a combinational methodology.

TiO-NiO composite nanorods were synthesized by combining hydrothermal growth of TiO nanorods and sputtering deposition of NiO film. Crystalline NiO coverage films with various thicknesses were sputter coated onto TiO nanorods by controlling NiO sputtering duration. The crystallographic analyses demonstrate that crystalline rutile TiO-cubic NiO composite nanorods were formed herein. In comparison with pristine TiO and NiO, the coverage of NiO crystals on the TiO nanorods led to an enhanced photodegradation activity of the TiO-NiO composites towards Rhodamine B dyes under irradiation. Moreover, the TiO-NiO composite nanorods with the adequate content of NiO coverage layer show superior gas-sensing responses to 25-200 ppm ammonia gas in comparison with those of the constituent counterparts. The experimental results herein demonstrate that decoration of NiO film on the surfaces of TiO nanorods with tunable coverage sizes via sputtering deposition is a promising approach to design TiO-NiO composite nanorods with desirable functionalities.