Synergetic interplay between metal (Pt) and nonmetal (C) species in codoped TiO2: A DFT+U study

GABRIELA F. CABEZA; CECILIA I. N. MORGADE

COMPUTATIONAL MATERIALS SCIENCE

ELSEVIER SCIENCE BV

Lugar: Bahia Blanca; Año: 2016 vol. 111 p. 513 - 524

0927-0256

The structural, energetic, magnetic and electronicproperties of Pt-C-doped and Pt/C-codoped TiO2 have been studiedusing first-principle calculations to elucidate the effect of themetal-nonmetal interactions. Compared with othernon-metals, C-doping induces the formation of complex structures on titania.From the analysis of the electronic structures of the C-doping system, band gapnarrowing as well as the formation of localized gap states are observed in it.This allows us to predict greater photocatalitical activity of the C dopedtitania than the undoped titanium dioxide. The calculated results are inagreement with the experimental absorptions observed in the UV-visible diffuse reflectance spectroscopyspectra. Based on our results, the main findings relating to Pt/C codoping arethe formation of highly symmetric coordination-like compounds and the formationof impurity states in the band gap, which are propitious for the separation ofphotoexcited electron?hole pairs. These phenomena are especially remarkable inthe case of Pt/C@Ti-codoped TiO2. This system would be the mosteffective for the redox reaction of H2O to produce H2 andO2 because it presents the greatest narrowing of the band gap, thelower shift of the conduction band and it is the only one that favorablymodifies the position of valence band. All are necessary conditions for the reactionmentioned.