Structural analysis and characterization of layer perovskite oxynitrides made from Dion-Jacobson oxide precursors
Structural analysis and characterization of layer perovskite oxynitrides made from Dion-Jacobson oxide precursors
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DOI：
10.1016/j.jssc.2005.05.012
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发表时间：
2005-07-01
影响因子：
3.3
通讯作者：
Mallouk, TE
中科院分区：
文献类型：
--
作者：
Schottenfeld, JA;Benesi, AJ;Mallouk, TE
本文报道了三层氧氮化物Ruddlesden-Popper相Rb（1+x）Ca（2）Nb（3）O（10-x）N（x）（.）在Rb 2CO 3存在下，通过在800 ℃下的氨解从Dion-Jacobson相RbCa 2Nb 3 O 10合成yH（2）O（x = 0.7-0.8，y = 0.4-0.6）。通过XPS、燃烧分析和MAS NMR证实了氮掺入层钙钛矿结构中。水含量通过热重分析测定，铷含量通过ICP-MS测定。在双层Dion-Jacobson氧化物RbLaNb 2 O 7中发生了类似的层状钙钛矿互变，得到Rb 1-xLaNb 2 O 7-（x）N（x）（.）yH（2）O（x = 0.7-0.8，y = 0.5-1.0）。这两种化合物都是空气和水分敏感的，通过氧化和水解反应迅速损失氮。用Rietveld方法对三层氧氮化物Rb（1.7）Ca（2）Nb（3）O（9.3）N（0.7）（-）0.5H（2）O的结构进行了修正，空间群为P4/mmm，a = 3.887（3），c = 18.65（1）。两层氧氮化物结构Rb（1.8）LaNb（2）O（6.3）N（0.7）（.）1.0H（2）O，空间群P4/mmm，a = 3.934（2），c = 14.697（2）埃。GSAS精修的同步辐射X射线粉末衍射数据表明，水分子之间的两层和三层Ruddlesden-Popper结构的Rb+离子的双层插入。光学带隙通过漫反射UV-vis测量两种材料。间接带隙为2.51 eV，直接带隙为2.99 eV的三层化合物。而对于两层化合物测量到2.29eV的间接带隙和2.84eV的直接带隙。在380 nm滤光下，以AgNO 3为牺牲电子受体，对该三层化合物进行光催化活性测试，测得其析氧量子产率为0.025%。(c)2005年爱思唯尔公司All rights reserved.
A three-layer oxynitride Ruddlesden-Popper phase Rb(1+x)Ca(2)Nb(3)O(10-x)N(x)(.)yH(2)O (x = 0.7-0.8, y = 0.4-0.6) was synthesized by ammonialysis at 800 degrees C from the Dion-Jacobson phase RbCa2Nb3O10 in the presence of Rb2CO3. 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 RbLaNb2O7 to yield Rb1-xLaNb2O7-(x)N(x)(.)yH(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(1.7)Ca(2)Nb(3)O(9.3)N(0.7)(-)0.5H(2)O was solved in space group P4/mmm with a = 3.887(3) and c = 18.65(1) angstrom, by Rietveld refinement of X-ray powder diffraction data. The two-layer oxynitride structure Rb(1.8)LaNb(2)O(6.3)N(0.7)(.)1.0H(2)O was also determined in space group P4/mmm with a = 3.934(2) and c = 14.697(2) angstrom. 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 2.51 eV and a direct band gap of 2.99 eV were found for the three-layer compound. while an indirect band gap of 2.29 eV and a direct band gap of 2.84 eV were measured for the two-layer compound. Photocatalytic activity tests of the three-layer compound under 380 nm pass filtered light with AgNO3 as a sacrificial electron acceptor gave a quantum yield of 0.025% for oxygen evolution. (c) 2005 Elsevier Inc. All rights reserved.