Onfroy Thomas, Clet Guillaume, Houalla Marwan
Laboratoire Catalyse et Spectrochimie (UMR CNRS 6506), ENSICAEN-Université de Caen, 6 Bd. du Maréchal Juin, 14050 Caen Cedex, France.
J Phys Chem B. 2005 Aug 4;109(30):14588-94. doi: 10.1021/jp0517347.
The development of the acidity and the relationship between acidity, catalytic activity, and the surface structure for niobium oxide supported on zirconia were investigated for a series of solids. The catalysts were active for 2-propanol dehydration only above a threshold in Nb loading. The acidity was studied by infrared spectroscopy of adsorbed 2,6-dimethylpyridine as a probe molecule, and the onset of activity was correlated with that of the formation of relatively strong Brønsted acid sites. The variation in the abundance of these sites also correlated with the catalytic activity. Raman, IR, and UV spectroscopy results indicated that the active sites were related to polymeric Nb surface species. These results were compared to those previously reported for the WO(x)/ZrO(2) catalysts.
研究了一系列负载在氧化锆上的氧化铌固体的酸度发展情况，以及酸度、催化活性和表面结构之间的关系。这些催化剂仅在铌负载量高于阈值时对2-丙醇脱水具有活性。通过吸附2,6-二甲基吡啶作为探针分子的红外光谱研究酸度，并且活性的起始与相对强的布朗斯台德酸位点的形成相关。这些位点丰度的变化也与催化活性相关。拉曼光谱、红外光谱和紫外光谱结果表明，活性位点与聚合态的铌表面物种有关。将这些结果与先前报道的WO(x)/ZrO(2)催化剂的结果进行了比较。
