Structural analysis and characterization of layer perovskite oxynitrides made from Dion-Jacobson oxide precursors

Journal Article · Fri Jul 15 00:00:00 EDT 2005 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2005.05.012· OSTI ID:20729032

Schottenfeld, Joshua A ^[1]; Benesi, Alan J ^[1]; Stephens, Peter W ^[2]; Chen, Gugang ^[3]; Eklund, Peter C ^[3]; Mallouk, Thomas E ^[1]

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1. Department of Chemistry, Pennsylvania State University, University Park, PA 16802 (United States)
2. Department of Physics and Astronomy, State University of New York, Stony Brook, New York 11794 (United States)
3. Departments of Physics, Pennsylvania State University, University Park, PA 16802 (United States)

A three-layer oxynitride Ruddlesden-Popper phase Rb{sub 1+x}Ca{sub 2}Nb{sub 3}O{sub 10-x}N{sub x}.yH{sub 2}O (x=0.7-0.8, y=0.4-0.6) was synthesized by ammonialysis at 800{sup o}C from the Dion-Jacobson phase RbCa{sub 2}Nb{sub 3}O{sub 10} in the presence of Rb{sub 2}CO{sub 3}. Incorporation of nitrogen into the layer perovskite structure was confirmed by XPS, combustion analysis, and MAS NMR. The water content was determined by thermal gravimetric analysis and the rubidium content by ICP-MS. A similar layered perovskite interconversion occurred in the two-layer Dion-Jacobson oxide RbLaNb{sub 2}O{sub 7} to yield Rb{sub 1+x}LaNb{sub 2}O{sub 7-x}N{sub x}.yH{sub 2}O (x=0.7-0.8, y=0.5-1.0). Both compounds were air- and moisture-sensitive, with rapid loss of nitrogen by oxidation and hydrolysis reactions. The structure of the three-layer oxynitride Rb{sub 1.7}Ca{sub 2}Nb{sub 3}O{sub 9.3}N{sub 0.7}.0.5H{sub 2}O was solved in space group P4/mmm with a=3.887(3) and c=18.65(1)A, by Rietveld refinement of X-ray powder diffraction data. The two-layer oxynitride structure Rb{sub 1.8}LaNb{sub 2}O{sub 6.3}N{sub 0.7}.1.0H{sub 2}O was also determined in space group P4/mmm with a=3.934(2) and c=14.697(2)A. GSAS refinement of synchrotron X-ray powder diffraction data showed that the water molecules were intercalated between a double layer of Rb+ ions in both the two- and three-layer Ruddlesden-Popper structures. Optical band gaps were measured by diffuse reflectance UV-vis for both materials. An indirect band gap of 2.51eV and a direct band gap of 2.99eV were found for the three-layer compound, while an indirect band gap of 2.29eV and a direct band gap of 2.84eV were measured for the two-layer compound. Photocatalytic activity tests of the three-layer compound under 380nm pass filtered light with AgNO{sub 3} as a sacrificial electron acceptor gave a quantum yield of 0.025% for oxygen evolution.

• OSTI ID: 20729032
• Journal Information: Journal of Solid State Chemistry, Vol. 178, Issue 7; Other Information: DOI: 10.1016/j.jssc.2005.05.012; PII: S0022-4596(05)00212-4; Copyright (c) 2005 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
BINDING ENERGY
COMBUSTION
HYDROLYSIS
ICP MASS SPECTROSCOPY
LAYERS
NITRIDES
NUCLEAR MAGNETIC RESONANCE
OXIDES
PEROVSKITE
RUBIDIUM CARBONATES
SILVER NITRATES
SPACE GROUPS
SYNCHROTRONS
TETRAGONAL LATTICES
THERMAL GRAVIMETRIC ANALYSIS
VALENCE
X-RAY DIFFRACTION
X-RAY PHOTOELECTRON SPECTROSCOPY