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应用FT-IR光谱及其差谱、DSC热分析以及催化选择性实验研究了不同配比的MoO_3-V_2O_5,MoO_3-TiO_2(锐钛矿型),MoO_3-WO_3和MoO_3-ZrO_2四种体系经不同温度焙烧后,界面过渡层非晶相分散的非单层结构及催化性能。FT-IR光谱及其差谱上出现了非晶相的特征吸收峰,并将其逐个与分子结构关联。DSC证明,在高于焙烧温度的升温扫描范围内(500～720℃),过渡层呈热介稳态,放热峰的出现与固熔体的形成及晶格畸变有关,但不存在表面及体相化学反应。以邻二甲苯选择性氧化制酸酐作为催化性能的反应探针,测定了转化率和选择性,表明非晶相分散的MoO_3和V_2O_5对反应有利,当配比处于分散阈值附近时选择性最佳。结合前文结果讨论了过渡层的非晶相分散机理和八面体非单层模型。
The different ratios of MoO_3-V_2O_5, MoO_3-TiO_2 (anatase), MoO_3-WO_3 and MoO_3-ZrO_2 were studied by FT-IR spectroscopy and their difference spectra, DSC thermal analysis and catalytic selectivity experiments Non - monolayer structure and catalytic performance of amorphous phase dispersed in interfacial transition layer after calcination at temperature. The characteristic absorption peaks of amorphous phase appear on the FT-IR spectrum and its difference spectrum, and are related to the molecular structure one by one. DSC shows that the transition layer is thermally metastable at a temperature range of 500-720 ° C higher than the calcination temperature. The appearance of the exothermic peak is related to the formation of solid solution and lattice distortion, but no surface and / Bulk chemical reaction. O-xylene was used as the reaction probe for the selective oxidation of the anhydride to the catalytic performance. The conversion and selectivity were determined. It was found that the amorphous phase dispersed MoO 3 and V 2 O 5 favored the reaction and the selectivity was best when the ratio was near the dispersion threshold . Combined with the results of the previous discussion, the transition layer amorphous phase dispersion mechanism and octahedral non-single-layer model.