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研究了酸性助剂对TiO2纳米管(TNT)负载的V2O5催化剂(V2O5/TNT)性能的影响, 发现经硫酸、磷酸或磷钨酸处理后, TNT的结构稳定, 但表面酸性和氧化-还原性发生了变化, 从而改变了甲醇选择氧化为甲缩醛的催化性能. 实验结果表明, V2O5/TNT催化剂经硫酸修饰和673 K焙烧, 其甲缩醛选择性显著提高, 且维持了较高的甲醇转化率. 催化剂表征表明, 高温焙烧促进了硫酸根与钒物种之间的强相互作用, 从而提高了催化剂的表面酸性而没有降低钒的氧化-还原性. 磷酸和磷钨酸修饰虽然也提高了V2O5/TNT催化剂的表面酸性, 但降低了其中钒氧化物的氧化-还原能力, 反而降低了催化剂的活性.
The effect of acidic auxiliaries on the performance of V2O5 / TNT supported on TiO2 nanotubes (TNT) was investigated. It was found that the structure of TNT was stable after treatment with sulfuric acid, phosphoric acid or phosphotungstic acid, but the surface acidity and oxidation-reduction Which changed the catalytic performance of selective oxidation of methanol to methylal.Experimental results show that the selectivity to methylal of V2O5 / TNT catalyst is significantly increased by sulfuric acid modification and 673 K calcination, and the higher methanol Conversion.The catalytic characterization showed that high temperature calcination promoted the strong interaction between sulfate and vanadium species and thus increased the surface acidity of the catalyst without reducing the oxidation-reduction of vanadium.The modification of phosphoric acid and phosphotungstic acid, though, also improved The surface acidity of V2O5 / TNT catalyst decreases the oxidation-reduction ability of vanadium oxide, but decreases the activity of the catalyst.