Work is dealing with the possibility to use rutile nanoparticles for photocatalytic decomposition of caffeine as a model contaminant. Rutile, a crystal modification of TiO2 has lower bandgap than anatase crystal form. This would mean that for the photocatalytic effect the visible light could be used, and not UV light like in anatase case. Using appropriate synthesis very small rutile nanoparticles, with high specific surface were directly obtained. Particles were characterised with transmission electron microscopy and microanalyis where 1-2 nm thick amorphous layer was found on the surface. Classically prepared rutile particles with thermally stimulated phase transformation from anatase have very clean and flat surface. We explained that the surface amorphous layer was the main reason why our rutile particles possess quite good photocatalytic properties and classically prepared rutile is practically inactive. The work was partially done at University of Porto, Portugal, where photocatalytic measurements were performed.
COBISS.SI-ID: 26672423
In the paper the synthesis, design and properties of TiO2 based microreactor is described. Firmly adhered TiO2 anatase layer was introduced using original two-steps synthesis. In the first step using anode oxidation the few hundreds of nm thick layer of TiO2 nanotube was formed. During second step hydrothermal synthesis was used to form few nm sized anatase nanoparticles at the top of the TiO2 nanotubes. The device was composed of autonomous UV light source (4 UV LED diodes) with corresponding controller, hermetical seal made of UV-transparent plexiglas and active channel, 250 microns wide and 39 cm long coated with anatase TiO2. Using electron microscopy and microanalysis techcniques (SEM, FIB, TEM) thorough microstructural investigation was performed where interfaces and individual layers were characterised. Between metal titania and TiO2 few nm sized rutile phase was found. Few hundreds nm thick layer composed of TiO2 nanotubes follow. At the top of the tubes, hydrothermally grown few nm sized anatase nanoparticles were present. In the paper the properties and aging of the reactor was reported. After year and a half of the intensive use, the reactor still exhibit 60% of starting photocatalytic efficiency.
COBISS.SI-ID: 26981415
In cooperation with colleagues from the University of Porto, Portugal we studied the photocatalytic degradation of caffeine as a model pollutant. The concentration of the caffeine could be easily followed using UV-VIS spectrophotometer. Different photocatalyst were used, various commercial grade nano particles and composites with the addition of the carbon nano tubes.
COBISS.SI-ID: 26271015