Examining the dual effect of copper nanoparticles and nitrogen doping on Cu@N-TiO2

The study of six compositions of Cu@N-TiO2with different amounts of copper and nitrogen synthesized using a sol–gel method is reported. X-ray diffraction patterns and Raman spectra indicated the formation of a single anatase TiO2phase in all materials without evidence of secondary phases including copper or nitrogen. Electron microscopy images showed a homogeneous distribution of the copper particles around a TiO2matrix, just as that the insertion of nitrogen did not have a significant effect on the morphology of the particles. X-ray photoelectron spectroscopy analysis confirmed that nitrogen was inserted in the atomic arrangement of titanium dioxide, while copper was presented mainly as metallic element on the TiO2surface. Characterization of the optical properties and photoactivity test confirm that band gap strongly depends on the copper and nitrogen content phenomenon attributed to the combined presence of modifiers over the TiO2surface and the promotion of a plasmonic effect, which displaced the absorption UV bands to higher wavelengths with respect to un-doped TiO2. The catalytic test performed using rhodamine-B as probe molecule, confirm that TiCuN2 and TiCuN3 samples exhibit the best decomposition percentages of 38 and 36 % respectively. Such results confirm the surface plasmon resonance effect associated to Cu particles on the TiO2as main cause in the increase in current along synthesized samples and the use of cyclic voltammetry technique to identify these effects between 0.0 and 1.5 V.