Electronic and Structural Properties of Highly Aluminum Ion Doped TiO2 Nanoparticles: A Combined Experimental and Theoretical Study

• Published in: Chemphyschem Vol. 15; no. 11; pp. 2267 - 2280
• Main Authors: de los Santos, Desireé M., Aguilar, Teresa, Sánchez-Coronilla, Antonio, Navas, Javier, Cruz Hernández, Norge, Alcántara, Rodrigo, Fernández-Lorenzo, Concha, Martín-Calleja, Joaquín
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 04.08.2014; WILEY‐VCH Verlag; Wiley; Wiley Subscription Services, Inc
• Subjects: Aerodynamics; Catalysis; Chemistry; Colloidal state and disperse state; density functional theory; doping; Exact sciences and technology; General and physical chemistry; oxygen vacancies; photocatalysis; Photochemistry; Physical and chemical studies. Granulometry. Electrokinetic phenomena; Physical chemistry of induced reactions (with radiations, particles and ultrasonics); Spectrum analysis; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; titanium; Oxygen; Electronic properties; Vacancy; Nanoparticle; Photocatalysis; titanium; Transition element compounds; Doping; Theoretical study; Experimental study; oxygen vacancies; Heterogeneous catalysis; density functional theory; Aluminium ion; Density functional method; Titanium oxide
• ISSN: 1439-4235; 1439-7641
• DOI: 10.1002/cphc.201402071

This study presents the experimental and theoretical study of highly internally Al‐doped TiO2 nanoparticles. Two synthesis methods were used and detailed characterization was performed. There were differences in the doping and the crystallinity, but the nanoparticles synthesized with the different methods share common features. Anatase to rutile transformation occurred at higher temperatures with Al doping. X‐ray photoelectron spectroscopy showed the generation of oxygen vacancies, which is an interesting feature in photocatalysis. In turn, the band‐gap energy and the valence band did not change appreciably. Periodic density functional calculations were performed to model the experimentally doped structures, the formation of the oxygen vacancies, and the band gap. Calculation of the density of states confirmed the experimental band‐gap energies. The theoretical results confirmed the presence of Ti4+ and Al3+. The charge density study and electron localization function analysis indicated that the inclusion of Al in the anatase structure resulted in a strengthening of the TiO bonds around the vacancy. TiO2 all doped up: Highly Al‐doped TiO2 nanoparticles are studied experimentally and theoretically. The crystallinity of TiO2 samples doped with up to 20.0 at % Al is maintained. Studies of the oxygen vacancies and supercells up to 191 atoms are optimized to simulate experimental stoichiometries. The theoretical results match the experimental data. The results provide useful insight into the photocatalytic fields of doped TiO2.