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用溶胶—凝胶法合成了非晶态Fe0 .5Al0 .5PO4 。用XRD和TPR表征了其结构和晶格氧的活性 ;用IR和TPD表征了CH4 在其表面上的吸附行为 ;用LSSR方法考察了CH4 直接氧化合成CH3 OH的反应规律。结果表明 ,Fe0 .5Al0 .5PO4 具有非晶态的结构 ,FePO4 和AlPO4 的微区被均匀地相互隔离 ,导致固体本身不具有长程有序性。非晶态的Fe0 .5Al0 .5PO4 与晶态的Fe0 .5Al0 .5PO4 相比 ,其晶格氧的活性大且活性氧的含量高。CH4 以分子态吸附于固体表面P =O键上 ,非晶态Fe0 .5Al0 .5PO4 表面上CH4 的吸附强度和吸附量都较晶态Fe0 .5Al0 .5PO4 上大。用 10 73cm- 1的激光激发固体表面P =O键 ,在 10 0℃以上CH4 的直接氧化反应顺利进行 ,CH3 OH保持高选择性。在相同的反应条件下 ,非晶态Fe0 .5Al0 .5PO4 能更有效地促进反应的进行 ,表明在激发相同表面化学键的情况下 ,固体表面材料的其它性质如粒度、比表面积和晶格氧的活性对反应也有一定程度的影响
The amorphous Fe0.5Al0.5PO4 was synthesized by sol-gel method. The structure and lattice oxygen activity of CH4 were characterized by XRD and TPR. The adsorption behavior of CH4 on its surface was characterized by IR and TPD. The reaction rule of CH4 direct oxidation to CH3OH was investigated by LSSR method. The results show that Fe0.5Al0.5PO4 has an amorphous structure, and the micro-regions of FePO4 and AlPO4 are evenly separated from each other, resulting in that the solid itself does not have long-range orderliness. Compared with the crystalline Fe0 .5Al0 .5PO4, the amorphous Fe0.5Al0.5PO4 has a large lattice oxygen activity and a high reactive oxygen species. CH4 molecular state adsorption on the solid surface P = O bond on the surface of amorphous Fe0 .5Al0 .5PO4 CH4 adsorption strength and adsorption capacity than crystalline Fe0 .5Al0. 5PO4 on the large. With 1073cm-1 laser excitation of the solid surface P = O bond, the direct oxidation of CH4 at 10 0 ℃ above the direct oxidation reaction, CH3 OH to maintain high selectivity. Under the same reaction conditions, the amorphous Fe0.5Al0.5PO4 can promote the reaction more effectively, indicating that other properties of the solid surface material such as particle size, specific surface area and lattice oxygen in the case of excitation of the same surface chemical bond Activity also has some effect on the reaction