First-Principles Characterization of Bi-based Photocatalysts: Bi₁₂TiO₂₀, Bi₂Ti₂O₇, and Bi₄Ti₃O₁₂

Abstract

The geometric, electronic, and optical properties of three Bi-based structures (Bi 12 TiO 20 , Bi 2 Ti 2 O 7 , and Bi 4 Ti 3 O 12 ) with and without C and N doping as possible photocatalytic material were investigated systemically by means of the first-principles DFT calculations within the GGA scheme to explore the origin of different band gaps and high photocatalytic activity under visible light observed in experiment. Our calculated results illuminate that BTO structures show an indirect band gap characteristic and the actual band gaps of BTO structures should be wider than 3.0 eV except for Bi 4 Ti 3 O 12 . C and N elements can be very easily introduced into the BTO lattices during the sample preparation process according to the very small defect formation energies, and the unintentional C or N doping may be responseble for the observed different band gaps and the high photocatalytic activity under visible light. Accordingly, it can be predicted that nonmetal element doping of BTO structures may improve photocatalytic activity under visible light and can be an excellent candidate for TiO 2.

Determination of the electronic, dielectric, and optical properties of sillenite Bi12TiO20 and perovskite-like Bi4Ti3O12 materials from hybrid first-principle calculations

“…[7][8][9][10][34][35][36] This result is distinctive from the small band gaps that were calculated using the standard PBE functional. 30,31,37 We emphasize here that our highly accurate characterization of these bismuth titanate compounds indicates that this material has remarkable photophysical properties, making it a promising material to be used in optoelectronic devices.…”

“…S7), 48 which were similarly reported in previous theoretical studies. 30,31,37 Alternatively, small increments in band gap by 0.2 and 0.04 eV for sillenite and perovskite-like structures, respectively, were obtained without taking spin-orbit coupling into consideration (Figs. S8 and S9).…”

“…takanabe@kaust.edu.sa electronic structure and band gap, which govern the photoconversion process, have not been well characterized. 17,[30][31][32][33] In the literature, their band gaps remain controversial, as they have been reported whether there is the presence 18,19 or absence 16 of a visible response. Furthermore, important characteristics such as the dielectric constant, charge carrier effective masses, and band edges have not been reported for these materials.…”

Экспериментальное исследование и ab initio расчет свойств Sc-, In-допированных титанатов висмута со структурой типа пирохлора

“…Ранее с помощью ab initio расчетов были получены данные об электронной структуре и оптических свой-ствах стехиометрического Bi 2 Ti 2 O 7 [1,16,[26][27][28][29][30][31][32]. Авторы упомянутых работ показали, что это соединение отно-сится к диэлектрикам с прямым электронным переходом и величиной запрещенной щели 2.6−2.85 eV [29,32].…”

Microwave synthesis of mesoporous WO3 doping with bismuth and photocatalytic oxidation of water to H2

“…In this paper, mesoporous WO 3 had been prepared by microwave heating. The Bi 3+ ion was chosen as an electron acceptor owing to its high stability in aqueous solutions, its excellent ability to absorb light and its highly reversible reduction on oxide surfaces [10]. This kind of mesostructured catalyst shows high photocatalytic activity for oxidation of water to H 2 .…”