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利用直接热插入法制备了MoO_3/十二烷基胺(DDA)插层复合材料并对其进行煅烧处理制备了MoO_3/C-N复合材料.研究了不同的煅烧条件对该复合材料的结构、组分及形貌的影响,结果表明在400~800℃之间进行煅烧,MoO_3/C-N复合材料的晶态结构发生了有序-无序-有序的变化,部分Mo的价态由+6降到+4或+2.当煅烧温度低于600℃时,主要是MoO_3层间十二烷基胺的碳化反应,MoO_3的层状结构仍然存在,但层间距变小.当煅烧温度高于600℃时,MoO_3与C发生氧化还原反应生成Mo2C,MoO_3的层状结构被破坏.在600℃煅烧处理时,随着煅烧时间的延长,有MoO_2晶体产生.煅烧升温速率对复合材料的结构影响不大.将不同煅烧条件制备的MoO_3/C-N复合材料应用于苯甲醇制备苯甲醛的催化研究,结果发现600℃煅烧2 h处理得到的MoO_3/C-N复合材料的催化效果最好,产物选择性单一,苯甲醛产率达30%,比未插层的MoO_3(8%)提高了近4倍,且该催化剂可多次重复使用.
MoO_3 / dodecylamine (DDA) intercalation composites were prepared by direct thermal insertion method and calcined to prepare MoO_3 / CN composites. The effects of different calcination conditions on the structure, The results show that the crystalline structure of MoO_3 / CN composites undergo an order-disorder-order change when calcined at 400 ~ 800 ℃, and the valence of some Mo decreases from +6 to +4 or +2. When the calcination temperature is lower than 600 ℃, it is mainly the carbonation reaction of MoO_3 interlayers, the lamellar structure of MoO_3 still exists, but the interlayer spacing becomes smaller.When the calcination temperature is higher than 600 ℃ , The layer structure of MoO_3 is destroyed by the redox reaction between MoO_3 and C. When calcined at 600 ℃, MoO_2 crystals are formed with the increase of calcination time.The calcination temperature has little effect on the structure of the composites The catalytic activity of MoO_3 / CN composites prepared by different calcination conditions for the preparation of benzaldehyde from benzyl alcohol showed that the catalytic effect of MoO_3 / CN composites calcined at 600 ℃ for 2 h was the best, Formaldehyde yields up to 30% are higher than those of unmixed MoO_3 (8%) Nearly 4-fold, and the catalyst can be used repeatedly.