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首页> 外文期刊>Applied Surface Science >Morphological And Textural Characterization Of Vanadium Oxide Supported On Zirconia By Ionic Exchange
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Morphological And Textural Characterization Of Vanadium Oxide Supported On Zirconia By Ionic Exchange

机译：离子交换法负载氧化锆上钒氧化物的形貌和组织结构表征

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Zirconia-supported vanadium oxide samples containing vanadium up to 6.8 wt.% were prepared by ionic exchange using aqueous solution of peroxovanadate complexes and hydrous zirconium oxide. The samples, heated at 823 K for 5 h in air, were studied by several techniques, including X-ray diffraction, surface area determinations, diffuse reflectance spectroscopy (UV-vis), Raman spectroscopy, pore size distribution measurements and atomic force microscopy. The results showed that the preparation procedure applied leads to good vanadium dispersion. The interaction between the anchored surface species and the support affects some ZrO_2 properties, including texture and phase transition. Depending on the vanadium loading, several species formed. In the most diluted sample small polyvanadate entities predominate, whereas at increasing vanadium loading (up to about 6 V atoms nm~(-2)) more condensed species formed yielding granular-type surface aggregates. At higher loading, granular-type particles and large flat structures, due to amorphous two- or three-dimensional polyvanadate species and ZrV_2O_7-like structures developed. Treatments with an ammonia solution specified that only a fraction of the . vanadium species (in a polymeric form) interacts with the zirconia surface. Atomic force microscopy directly imaged the formation of vanadium aggregates (superimposed to the interacting species) at increasing vanadium content and their removal by the ammonia leaching.
机译：通过使用过氧钒酸盐络合物和含水氧化锆的水溶液进行离子交换，制备了含钒量高达6.8 wt。％的氧化锆负载的氧化钒样品。通过几种技术研究了在823 K空气中加热5小时的样品，包括X射线衍射，表面积测定，漫反射光谱（UV-vis），拉曼光谱，孔径分布测量和原子力显微镜。结果表明，所采用的制备方法能使钒分散良好。锚固的表面物质和载体之间的相互作用会影响ZrO_2的某些特性，包括纹理和相变。根据钒的含量，形成了几种物质。在稀释度最高的样品中，较小的多钒酸盐实体占主导地位，而随着钒负载量的增加（高达约6 V原子nm〜（-2）），更多的缩合物种形成，产生颗粒型表面聚集体。在较高的载荷下，由于无定形的二维或三维多元钒酸盐物种和类似ZrV_2O_7的结构，形成了颗粒状颗粒和大的扁平结构。用氨水处理时只能吸收少量的氨水。钒物质（以聚合形式）与氧化锆表面相互作用。原子力显微镜直接成像了钒含量增加时钒团聚体的形成（叠加在相互作用的物种上），并通过氨浸出将其除去。

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