The Electronic Structures and Optical Properties of Alkaline-Earth Metals Doped Anatase TiO2: A Comparative Study of Screened Hybrid Functional and Generalized Gradient Approximation

Abstract

Alkaline-earth metallic dopant can improve the performance of anatase TiO2 in photocatalysis and solar cells. Aiming to understand doping mechanisms, the dopant formation energies, electronic structures, and optical properties for Be, Mg, Ca, Sr, and Ba doped anatase TiO2 are investigated by using density functional theory calculations with the HSE06 and PBE functionals. By combining our results with those of previous studies, the HSE06 functional provides a better description of electronic structures. The calculated formation energies indicate that the substitution of a lattice Ti with an AEM atom is energetically favorable under O-rich growth conditions. The electronic structures suggest that, AEM dopants shift the valence bands (VBs) to higher energy, and the dopant-state energies for the cases of Ca, Sr, and Ba are quite higher than Fermi levels, while the Be and Mg dopants result into the spin polarized gap states near the top of VBs. The components of VBs and dopant-states support that the AEM dopants are active in inter-band transitions with lower energy excitations. As to optical properties, Ca/Sr/Ba are more effective than Be/Mg to enhance absorbance in visible region, but the Be/Mg are superior to Ca/Sr/Ba for the absorbance improvement in near-IR region.

Effect of Ru, Rh, Mo, and Pd Adsorption on the Electronic and Optical Properties of Anatase TiO2(101): A DFT Investigation

“…Adsorption of metals onto TiO 2 are an effective method to narrow the band gap of TiO 2 and improve the photocatalytic activity [ 23 ]. Recently, theoretical calculations have been widely used to study the photocatalytic principle of metal being doped into the inner lattice of TiO 2 [ 24 ]. The results of the theoretical calculations demonstrated the mechanism of the photocatalytic activity intensified by the doped metal cluster.…”

Effects of Transition Metal Substituents on Interfacial and Electronic Structure of CH3NH3PbI3/TiO2 Interface: A First-Principles Comparative Study

“…Till date, the atomic arrangement of the CH 3 NH 3 PbI 3 /TiO 2 is still unclear due to limit of the experimental techniques. Based on previous studies of the transition metal-substituted TiO 2 surface [50,51], the interfacial configurations were carefully designed to make the substituent effect more prominent at the interface region. We assume that all six different transition metal ions partially substituted at the Ti 4+ sites (Ti 5C or Ti 6C ) correspond to the substitution concentration of 17% and the supercell is represented by Ti 0.83 M 0.17 O 2 ( M = Zn 2+ , Y 3+ , Zr 4+ , Nb 5+ , Ru 4+ , W 6+ ).…”

Suvremena sredstva za dekontaminaciju bojnih otrova

“…Istraživanja su pokazala da on sam nema toliko reaktivnih mjesta kao drugi metalni oksidi u formi nanomaterijala, ali u formi nanocijevi pokazuje znatno bolja adsorpcijska svojstva bez smanjenja specifične površine. [28][29][30][31][32][33] Za razliku od ostalih metalnih oksida, TiO 2 u uvjetima prisutnosti zraka i/ili vlage pokazuje izvanrednu stabilnost. Nanokristalna i nanočestična forma imaju sklonost formiranju koagulata, čime je ograničen broj dostupnih aktivnih mjesta na površini.…”

“…34 Hibridni materijali dobiveni modifikacijom nanocijevi TiO 2 s određenim metalnim ionima kao što su Ru 3+ , Ni 2+ , Cu 2+ , Ag + , Mn 2+ i Co 2+ pokazali su dodatno katalitičko svojstvo i veću brzinu hidrolize bojnih otrova GA i HD u vodenim otopinama. [5][6]33 Nanocijevi Fig. 7 -Proposed mechanism of reactive adsorption of CP on the surface of titanium oxide 37…”