载体TiO_2晶型对甲醇选择氧化性能的影响

Effect of TiO_2 crystalline type on selective oxidation performance of methanol

以比表面积相近的锐钛和金红石Ti O2为载体,制备了负载钒氧和硫酸根物种的催化剂,比较了催化甲醇选择氧化的性能。结果表明,与金红石负载的催化剂相比,锐钛负载的钒氧催化剂具有较好的氧化性和酸性,在反应温度为433 K时,甲醇氧化的转化率较为接近,但产物中甲醛和甲酸甲酯的总选择性为63%,高于金红石负载催化剂上的54%。硫酸根的引入增加了甲醇转化率和甲缩醛选择性,在金红石负载型催化剂上尤为明显,甲缩醛选择性提高至88%。

Using separately anatase and rutile TiO2 with similar specific surface areas as supporter,the catalysts supported vanadia and sulfate species are prepared. Their catalytic behaviors for the selective oxidation of methanol are evaluated and compared. It is found that anatase TiO2 supported vanadia catalyst exhibits superior redox and acidity properties than rutile TiO2 supported catalyst. Although these un-doped sulfate catalysts supported by two supporters exhibit a similar conversion of methanol oxidation at 433 K,total selectivity of formaldehyde and methyl formate for the anatase TiO2 based catalyst can reach 63%,higher than the 54% selectivity for rutile TiO2 based catalyst. Addition of sulfate further enhances the conversion of methanol and the selectivity to dimethoxymethane,which is more significant over rutile TiO2 based catalyst that can improve the selectivity of dimethoxymethane to as high as 88%.