Ca₂PbGa₈O₁₅: Rational Design, Synthesis, and Structure Determination of a Purely Tetrahedra‐Based Intergrowth Oxide

Abstract

Intergrowth oxides, like Aurivillius, Ruddlesden–Popper phase, comprise functional layers and exhibit interesting physical properties. The hitherto known intergrowth structures mainly were composed of closed‐packing of oxygen ions, and it is very challenging to develop new types of intergrowth structures. We proposed the possible match between the tridymite and grossite, both of which are purely tetrahedra‐based structures. We synthesized Ca2PbGa8O15 ((Ca0.5Pb0.5Ga2O4)2(CaGa4O7)) and its structure was solved by ab‐initio method. Pb2+ is vitally important to stabilize this first example of tetrahedra‐based intergrowth oxide. The appropriate size difference between Pb2+ and Ca2+ causes the layered type cationic ordering, and reduced the thermodynamic potential, in addition, the high hybridization between Pb 6s6p and O 2p orbitals further consolidate the covalency of the tetrahedra‐base framework.

Solid oxide proton conductors beyond perovskites

“…Further examples are constituted by reports of proton conductivity in acceptor doped Gd3-xAxGaO6 (A = Ca, Sr), of which structure is composed by distorted isolated GaO4 tetrahedra 182 , and in cuspidines of composition La4Ga2-xTixO9+x/2, which present corner-sharing Ga2O7 polyhedral units 183 . The Ga 3+ cation has a strong preference for tetrahedral coordination 184 , with the structures of several gallates containing either isolated tetrahedra or different types of corner-sharing GaO4 polyhedral units linkages 185,186,187,188 .…”

First-Principles Calculations on Narrow-Band Gap d10 Metal Oxides for Photocatalytic H2 Production: Role of Unusual In2+ Cations in Band Engineering

“…Beyond that, LP cations occasionally incorporate into the structural framework constructed by d 10 metal MO 4 (M = Ga, Zn, etc.) tetrahedrons, for example, CaPbZn 2 Ga 2 O 7 and Ca 2 PbGa 8 O 15 . , Given the strong covalent interaction between d 10 metal and oxygen atoms, the band gap value is still too big to absorb visible light. Therefore, the development of LP cation-based metal oxides with a narrow band gap and efficient carrier migration ability remains an ongoing challenge.…”

“…The new VBM is made up of occupied Pb/Bi-6s orbitals or Sn-5s orbitals, which raise the VBM and narrows the band gap. 23,24 Given the strong covalent interaction between d 10 metal and oxygen atoms, the band gap value is still too big to absorb visible light. Therefore, the development of LP cation-based metal oxides with a narrow band gap and efficient carrier migration ability remains an ongoing challenge.…”

Highly improved photocatalytic degradation of rhodamine B over Bi2Ga4−xFexO9 solid solutions under visible light irradiation

“…[9][10][11][12][13][14] However, a majority of semiconductors, such as TiO 2 , Ca 2 PbGa 8 O 15 , and ZnO, only have a response under ultraviolet light irradiation. [15][16][17] The ultraviolet spectrum and visible spectrum account for 4% and 46% of the solar spectrum, respectively. 18 Hence, discovering a new photocatalyst for the photocatalytic degradation reaction is an event of signicance.…”