工业氨肟化工艺失活HTS分子筛的结构特征和Ti物种状态

采用XRD及其Rietveld全谱拟合、低温N₂吸附-脱附、XPS、TEM（包括EFTEM和HRTEM）、UV-Vis等手段对失活HTS分子筛的晶胞参数、骨架结构、颗粒形貌和Ti物种的位置与状态进行分析。结果表明， HTS分子筛失活后，其拓扑结构保存完整，且晶胞参数未发生明显变化，但部分微孔结构发生溶解，介孔体积增大，比表面积略有下降。HTS分子筛失活后，部分骨架Ti物种转变为非骨架Ti物种，富集且高度分散于分子筛颗粒形成小碎片，可以初步判定该碎片为高度分散的无定型TiO₂或TiO₂-SiO₂氧化物。

Structure and Chemical State of Ti Species in Deactivated HTS Zeolite From Industrial Ammoxidation Processing

Multiple characterization methods, including XRD and its Rietveld whole pattern fitting, low-temperature N₂ adsorption-desorption, XPS, TEM(EFTEM, HRTEM) and UV-Vis spectroscopy, were introduced to investigate the characteristics, such as framework structure, crystal parameters, the morphology and chemical state of Ti species, of deactivated HTS zeolite from industrial cyclohexanone ammoxidation processing. The results showed that the MFI topological structure and crystal volume of deactivated HTS zeolite remained almost the same as that of fresh one, while some micropores of zeolite transformed into mesopores, resulting in the increase of mesopore volume and the decrease of specific surface area. At the same time the framework Ti transformed into non-framework Ti, forming highly scattered Ti aggregates on zeolite particle, which were considered as amorphous TiO₂ or TiO₂-SiO₂ oxides.