MATOS, J.; CAMPOS, K.; MONTAÑA, R., TITIRICI, M.M.:
Proceedings, Carbon for Energy Storage and Environment Protection – CESEP’2017, October 2017, Page 126.
Theoretical estimations of the density of states by DFT + U approach were performed. Electron charges and energy band gap of pristine anatase TiO2 and C-doped TiO2 were estimated and a decrease from 3.14 to 2.94 eV in a Ti15O32C super-cell in comparison than pristine anatase TiO2 was found. Results showed that doping of crystalline framework in anatase TiO2 clearly changes the density of states around oxygen as of function of carbon doping. Correlations of theoretical estimations with the experimental photocatalytic activity  in the methylene blue and phenol photo oxidation under solar irradiation were found and associated with a decrease in the energy band gap in the semiconductor explaining the red-shift detected in the UV-Visible diffuse reflectance (UV-Vis/DR) absorption spectra and the increase in the photocatalytic activity of hybrid C-doped nanostructured TiO2-based materials in the photodegradation of phenol and methylene blue. The visible light response of C- doped TiO2 has been also associated with the presence of 2p orbitals of C atom. Theoretical estimations also confirmed that C-doped TiO2 became as quantum-dots materials and therefore, the control of structural defects in the TiO2 framework can be used as a valuable tool for the synthesis of electrodes for the quantum-dots sensitized solar cells.