Impact Factor:0.0
Journal:Journal of Colloid and Interface Science
Key Words:Two-dimensional perovskite oxynitride photocatalystBonded heterostructureElectronic structureCarrier transferVisible-light absorptionFirst-principles calculations
Abstract:Searching for promising visible-light photocatalysts for overall water splitting into hydrogen and oxygen is a very challenging task to solve the energy crisis and environment pollution. The widely-used tantalate and niobate perovskite photocatalysts have two drawbacks, i.e., the large energy band gap (3.2–4.6 eV) and low electron (hole) mobility 102 (101) cm2 V−1 s−1, which greatly limit their photocatalytic performance. Here, based on the powerful first-principles and accurate GW calculations, we design several novel two-dimensional (2D) Ruddlesden-Popper (RP) type (n = 1) perovskite oxynitrides A2BO3N (A = Ca, Sr, Ba and B = Ta, Nb) and their bonded heterostructures and comprehensively investigate their interlayer coupling, electronic structures, transport and photocatalytic characteristics. We find that 2D A2BO3N oxynitrides have a reduced direct band gap at -point, especially for three-layer (3L) Ba2NbO3N and 1L-Sr2NbO3N/1L-Ba2NbO3N bonded heterostructure with the optimized band gap 2.0 eV. Compared with tantalate and niobate perovskite oxides, the electron (hole) mobility increases 1–2 orders of magnitude up to 103–104 (102–103) cm2 V−1 s−1. A fast electron-hole vertical transport across the heterointerface and remarkable electron-hole separation can be realized in 1L-Sr2NbO3N/1L-Ba2NbO3N bonded heterostructure due to its strong interface Ba-O and Sr-O bonds and type-II band offset. Compared with the well-known photocatalysts, such as BiVO4 and MoS2/g-C3N4, an improved optical absorption (8  104 cm−1) in A2BO3N is obtained in the visible region. The 2D RP-type perovskite oxynitrides 3L Ba2NbO3N and 1L-Sr2NbO3N/1L-Ba2NbO3N are powerful visible-light photocatalysts for overall water splitting.
Indexed by:Journal paper
Discipline:Natural Science
First-Level Discipline:Physics
Volume:546
Page Number:20-31
Translation or Not:no
Included Journals:SCI
Date of Publication:2019-06-15