Effects of Cs-substitution and partial reduction on catalytic performance of Keggin-type phosphomolybdic polyoxometalates for selective oxidation of isobutane

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• 作者：Shizhe Liu ; Lu Chen ; Guowei Wang ; Jianwei Liu ; Yanan Gao ; Chunyi Li ; ^{chyli_upc@126.com" class="auth_mail" title="E-mail the corresponding author} ; Honghong Shan
• 关键词：Isobutane ; Selective oxidation ; Methacrylic acid ; Polyoxometalate
• 刊名：Journal of Energy Chemistry
• 出版年：2016
• 出版时间：January 2016
• 年：2016
• 卷：25
• 期：1
• 页码：85-92
• 全文大小：803 K

文摘

The catalytic performance of Cs-substituted phosphomolybdic salts was studied for selective oxidation of isobutane. The results of activity tests revealed that 360 °C was the optimal reaction temperature. It was demonstrated that oxidizing sites not only took dominating part in the activation of isobutane, but also influenced the product distribution. Besides, appropriate Cs addition led to moderate acidity of catalysts, favoring the selectivity to desired products. Furthermore, to obtain partially reduced catalysts, different calcination atmospheres were investigated and certain proportion of Mo⁵⁺ produced during calcination was crucial for the redox reaction. The catalyst calcined in N₂ showed the highest yield of MAA (7.0%). Fe-substitution enhanced the activity of catalysts by rapid reoxidation of Mo⁵⁺.