Photoactivity of titanium dioxide films grown by cathodic arc doped with Cu and N

ARIEL KLEIMAN; DARINA MANOVA; STEPHAN MÄNDL; J M MEICHTRY; MARTA I LITTER; ADRIANA MÁRQUEZ

Garmisch-Partenkirchen

Conferencia; 14th International Conference on Plasma Surface Engineering (PSE 2014); 2014

Titanium dioxide is a very attractive material for the remediation of environmental pollutants, either in gas phase or in water, as well as for the development of anti-fogging and self-cleaning surfaces. The structure, composition and morphology of the films have a strong influence on the photoactivity of the material. Doping with metallic and nonmetallic species enables TiO2 to be sensitive to visible light extending the photoactivity of the material. Cathodic arc deposition (CAD) has demonstrated to be an efficient technique to produce TiO2 thin films due to its high deposition rate and high adhesion of the coatings. On the other hand, one method that allows doping metallic and nonmetallic trace impurity in films is plasma immersion ion implantation (PIII). In this work, combining CAD and PIII, TiO2 films doped with Cu and N were prepared on glass substrates with the aim of evaluating their photoactivity. The TiO2 films were grown by CAD with a Ti cathode in an O2 environment (~2 Pa) employing a 100 A DC arc. The substrates were kept at 300ºC and the exposure time was varied in order to attain different film thicknesses. After deposition, the samples were submitted to a pulsed glow discharge produced in a N2 atmosphere (~100 Pa) by applying pulses of 8 kV, at 200 Hz, with duration of 50 μs. Cu and Ti grids were located in front of the sample in order to enhance the effect of the biasing. The samples were heated at 300ºC while immersed in the plasma for 120 min. The films were analyzed by SIMS and AFM. Transmittance measurements in the UV-visible range were also performed. TiO2 films of ~ 400 nm thicknesses, after being exposed to the glow discharge with the copper grid, showed the presence of Cu along all their depth, and the absorbance spectrum presented a shift to the visible range. The photocatalytic activity was evaluated through the efficiency to degradate phenol and to reduce Cr(VI) in the presence of EDTA, under both UV-Vis and Vis irradiation.