An ab initio DFT perspective on experimentally synthesized CuBi₂O₄

Abstract

A comprehensive density functional theory guided experimental study of copper bismuth oxide CuBi2O4 to gain a better understanding of its functional properties relevant to photocatalytic activity.

Comprehensive First-Principles Modeling of Experimentally Synthesized BiPO4 Polymorphs

“…The elastic tensors were simulated for the GGA-PBE and GGA-PBEsol functionals. For all BS simulations based on hybrid functionals, the use of WANNIER90 tool kept the computation tractable. ,− The linear optical properties were estimated from the complex dielectric constant using GGA-PBE, GGA-PBEsol, GGA-PBE+SOC, HSE06, PBE-HF10%, and PBE-HF7%+SOC. ,,− …”

A combined first principles and experimental approach to Bi2WO6

“… 28,31–37 The GGA-PBE functional leads to localized d orbital binding energy underestimation that inflates its hybridization with p orbitals. 16,17,38–40 This spurious p–d coupling enhancement shifts the valence band maximum (VBM) up in energy, leading to band gap narrowing effects. 41 Moreover, the W-5d orbitals in BWO are less spatially localized than many 3d orbitals present in transition metals.…”

“… 14,15 The first principles simulations using density functional theory (DFT) can serve as an indispensable tool for understanding the functional properties of BWO. 16,17 The accuracy of DFT simulations suffers critically due to the improper modeling of partially filled W-5d orbitals in BWO for generalized gradient approximation (GGA) of Perdew–Burke–Ernzerhof (PBE). 18,19 The Hubbard interaction corrected GGA-PBE+ U d version, where the U d is applied to the W-5d, was used to study polaron formation effects, seems to underestimate the electronic band gap of bulk BWO measured from the density of states (DOS) compared to the experimental observations.…”

Spectroelectrochemical Identification of CuO Impurities Catalyzing Water Reduction on CuBi2O4 Photocathodes

“…The band structure consists of Cu-3d and O-2p hybridization in the conduction band responsible for water reduction and the hybridized O-2p, Cu-3d, Bi 5d, and Bi6s orbitals in the valence band. 4 The complex band structure with multiple orbital components narrows the band gap and therefore extends the optical absorption in both the visible and near-infrared regions. 5 Moreover, CuBi 2 O 4 exhibits a photocurrent onset ranging between 1.1 and 1.4 V RHE significantly more positive than other p-type photocathode materials, including gallium phosphide (GaP), p-type silicon, and copper(I) oxide (Cu 2 O).…”

“…The conduction band is located at −0.3 V versus reversible hydrogen potential (RHE), showing a more negative potential than the redox potential for proton reduction, providing sufficient driving force for H 2 production. The band structure consists of Cu-3d and O-2p hybridization in the conduction band responsible for water reduction and the hybridized O-2p, Cu-3d, Bi 5d, and Bi6s orbitals in the valence band . The complex band structure with multiple orbital components narrows the band gap and therefore extends the optical absorption in both the visible and near-infrared regions .…”