摘要
在丙烷选择氧化制丙烯酸催化剂MoVTeNbOx的活性相M1基础上掺杂一定量的Cr,当Cr/Nb摩尔比为0.002时,催化剂具有很高的丙烯酸选择性(78.3%)和收率(50.7%);并采用X射线衍射、X射线光电子能谱、程序升温还原、O2程序升温脱附、NH3程序升温脱附和异丙醇氧化等手段对催化剂的构效关系进行了探讨.结果表明,适量Cr的添加可调节催化剂表面Mo6+,V5+和Te4+等物种含量,提高催化剂的氧化能力,使丙烷转化率增加.同时,适量Cr的添加使得催化剂表面酸强度下降,酸性位点数量减少,从而抑制丙烯酸的深度氧化,提高了丙烯酸选择性.
The catalytic performance of active MoVTeNbOx catalysts containing an M1 phase in the partial oxidation of propane to acrylic acid (AA) was greatly improved when an optimal amount of Cr was added. The catalyst containing Cr/Nb (molar ratio=0.002) showed good selectivity (78.3%) and high AA yield (50.7%). The catalysts were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, H2 temperature-programmed reduction, O2 and NH3 temperature-programmed de-sorption, and oxidation of 2-propanol. The relationship between the catalyst structure and catalytic properties was investigated. The results indicated that the amounts of Mo6+, V5+and Te4+species on the catalyst surface were adjusted, and oxidation activity of the catalyst increased, as a result of doping with an appropriate amount Cr, which promoted propane activation. The acid strength be-came weaker, and the number of acid sites on the catalyst surface decreased, which suppressed AA oxidation and improved the selectivity for AA.
出处
《催化学报》
CSCD
北大核心
2013年第12期2183-2191,共9页
基金
supported by the National Natural Science Foundation of China(21173186)~~
