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首页> 外文期刊>Applied Catalysis, A. General: An International Journal Devoted to Catalytic Science and Its Applications >The influence of the preparation method on the structural, acidic and redox properties of V2O5-TiO2/SO_4~(2-) catalysts
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The influence of the preparation method on the structural, acidic and redox properties of V2O5-TiO2/SO_4~(2-) catalysts

机译：制备方法对V2O5-TiO2 / SO_4〜（2-）催化剂的结构，酸性和氧化还原性能的影响

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摘要

The introduction of sulfates into vanadia-titania catalysts and the influence of the preparation method on the properties of the sulfated samples have been studied. Series of V2O5-TiO2/SO4~(2-) (VTiS) catalysts were prepared by co-precipitation, sol-gel and mechanical grinding methods and calcined at different temperatures. Their structural properties were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). Co-precipitation was by far the best preparation method in terms of maximizing the surface area and the mesoporosity. Temperature-programmed reduction (TPR) revealed that only the vanadia species were reducible. The results from XRD and FT-IR showed that V2O5 was well dispersed on the surface of TiO2. XPS showed that the surface vanadium oxide was composed of stoichiometric V2O4 and V2O5, as well as V2O3 species especially for the samples prepared by mechanical grinding. Meanwhile, titanium was present in its fully oxidized state in all the VTiS samples, and the sulfur-containing species presented an oxidation state of+6. The reaction of isopropanol (IPA) conversion in air was used to characterize the surface acid/base and redox properties. The higher activity for the IPA conversion over the VTiS catalysts as compared to TiO2 was possibly due to the generation of redox sites upon the addition of V2O5. Moreover, the surface acidic properties were enhanced and the redox properties weakened upon addition of SO_4~(2-) species.
机译：研究了将硫酸盐引入钒-二氧化钛催化剂中以及制备方法对硫酸盐样品性能的影响。采用共沉淀法，溶胶-凝胶法和机械研磨法制备了一系列V2O5-TiO2 / SO4〜（2-）（VTiS）催化剂，并在不同温度下煅烧。通过X射线衍射（XRD），傅立叶变换红外光谱（FT-IR），热重分析（TGA）和X射线光电子能谱（XPS）表征了它们的结构性质。就最大表面积和中孔性而言，共沉淀是迄今为止最好的制备方法。程序升温还原（TPR）表明只有钒物种是可还原的。 XRD和FT-IR的结果表明，V2O5分散在TiO2表面。 XPS显示表面钒氧化物由化学计量的V2O4和V2O5以及V2O3种类组成，特别是对于通过机械研磨制备的样品。同时，在所有VTiS样品中，钛均以其完全氧化态存在，而含硫物质的氧化态为+6。异丙醇（IPA）在空气中的转化反应用于表征表面酸/碱和氧化还原特性。与TiO2相比，VTiS催化剂对IPA的转化活性更高，这可能是由于加入V2O5产生了氧化还原位。此外，加入SO_4〜（2-）后，表面酸性增强，氧化还原性能下降。

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