钙钛矿型铋层状氧化物新结构变体LiBi4M3O14（M = Nb，Ta）的合成、结构及光催化性能

Synthesis, structure, and photocatalysis in a new structural variant of the Aurivillius phase: LiBi4M3O14 (M = Nb, Ta).

作者信息

Muktha B, Priya M H, Madras Giridhar, Guru Row T N

机构信息

Solid State and Structural Chemistry Unit and Department of Chemical Engineering, Indian Institute of Science, Bangalore 560012, India.

出版信息

J Phys Chem B. 2005 Jun 16;109(23):11442-9. doi: 10.1021/jp051228h.

DOI:10.1021/jp051228h

PMID:16852400

Abstract

Two new compounds, LiBi4Nb3O14 and LiBi4Ta3O14, have been synthesized by the solid-state method, using Li2CO3, Bi2O3, and M2O5 (M = Nb, Ta) in stoichiometric quantities. These compounds crystallize in the monoclinic C2/c space group with a = 13.035(3) A, b = 7.647(2) A, c = 12.217(3) A, beta = 101.512(4) degrees , V = 1193.4(5) A3 , and Z = 4 and a = 13.016(2) A, b = 7.583(1) A, c = 12.226(2) A, beta = 101.477(3) degrees , V = 1182.6(5) A3, and Z = 4, respectively. These are isostructural and the structure along the b axis consists of layers of [Bi2O2]2+ units separated by layers of LiO4 tetrahedra and NbO6 octahedra hence depicting an unusual variation in the Aurivillius phase isolated for the first time. The presence of lithium has been confirmed by 7Li NMR studies. ac impedance measurements and variable temperature (7)Li NMR studies indicate oxygen ion conductivity in these materials. The UV-visible spectra suggest a band gap of 3.0 eV for LiBi4Nb3O14 and 3.5 eV for LiBi4Ta3O14, respectively, and the associated studies on degradation of dyes and phenols render these materials suitable for photocatalysis.

摘要

通过固态法，使用化学计量比的Li₂CO₃、Bi₂O₃和M₂O₅（M = Nb，Ta）合成了两种新化合物LiBi₄Nb₃O₁₄和LiBi₄Ta₃O₁₄。这些化合物结晶于单斜C2/c空间群，其a = 13.035(3) Å，b = 7.647(2) Å，c = 12.217(3) Å，β = 101.512(4)°，V = 1193.4(5) Å³，Z = 4，以及a = 13.016(2) Å，b = 7.583(1) Å，c = 12.226(2) Å，β = 101.477(3)°，V = 1182.6(5) Å³，Z = 4。它们是同构的，沿b轴的结构由[Bi₂O₂]²⁺单元层组成，这些单元层被LiO₄四面体层和NbO₆八面体层隔开，因此首次展示了Aurivillius相中一种不寻常的变体。通过⁷Li NMR研究证实了锂的存在。交流阻抗测量和变温⁷Li NMR研究表明这些材料中存在氧离子传导性。紫外可见光谱表明LiBi₄Nb₃O₁₄的带隙为3.0 eV，LiBi₄Ta₃O₁₄的带隙为3.5 eV，并且关于染料和酚类降解的相关研究表明这些材料适用于光催化。