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

A. KLEIMAN; D. MANOVA; S. MÄNDL; J.M. MEICHTRY; M. I. LITTER; A. MARQUEZ

Congreso; 14 International Conference on Plasma Surface Engineering; 2014

Titanium dioxide is a very attractive material for the remediation of environmental pollutants, either in gases or water or for the development of anti-fogging and self-cleaning surfaces. The structure, composition, and surface morphology of the films have a strong influence on the photoactivity of the surfaces. The doping of TiO2 with metallic and nonmetallic species contributes to render it sensitive to visible light by enhancing the surface photoactivy.Cathodic arc deposition (CAD) has demonstrated to be an efficient technique to produce TiO2thin films due to its high deposition rate and the high adherence of the coatings; on the other hand one of the methods that allows to dope metallic and nonmetallic trace impurity in films is plasma immersion ion implantation.In this work TiO2 films doped with copper and nitrogen on glass substrates, prepared combining CAD and ion implantation by immersion in plasmas generated with a pulsed glow dischargewere studied with the aim of characterizing their photoactivity. The TiO2 films were grown in anoxygen environment (~2 Pa) employing a 100 A continuous arc with the substrate at 300 ºC.The glass substrates were exposed to the arc discharge from 90 to 360 s in steps of 90 s, waiting 300 s between two consecutive steps. The pulsed glow discharge was produced in a nitrogen atmosphere (~100 Pa) by applying voltage pulses of 8kV, at 200Hz with duration of 50 s on a grid located in front of the sample. Copper and titanium grids were employed. The samples heated at 300 ºC have been immersed in the plasma for 120min. The element profiles of the films were analyzed by secondary ion mass spectrometry (SIMS), the morphology was observed by atomic force microscopy (AFM) and transmittance measurements in the UV-visible range were also performed. TiO2 films of ~ 400 nm thickness after being exposed to the glow discharge with the copper grid shown the presence of Cu along all their depth and the light absorption presented a shift to the visible range. The photoacatalytic activity was evaluated by the efficiency to reduce hexavalent chromium.