TiO_2负载氮化钴钼催化剂的制备及其加氢脱氧性能

Preparation of TiO_2 Supported CoMo Nitride Catalyst and Its Reactivity in Hydrodeoxygenation

利用TiO2负载CoMo氧化物在NH3气流中进行程序升温反应,制备了一系列不同Co负载量的氮化CoMo/TiO2催化剂,采用BET和XRD对其进行了表征.以苯酚为模型化合物,考察了氮化CoMo/TiO2催化剂的加氢脱氧性能,采用拟一级反应动力学对苯酚消耗反应速率常数进行了拟合.结果表明:Co3Mo3N是由CoMoO4氮化生成,而不是由CoO和MoO3混合氧化物氮化生成.随着Co的加入,在催化剂中形成了双金属氮化物新相Co3MO3N.Co的加入对于改变催化剂的比表面积大小和加氢脱氧性能起到了正反两方面的作用.不同催化剂加氢脱氧的反应速率大小顺序为:Co4Mo12>Co6Mo12>Co2Mo12>Co8Mo12>Co0Mo12>thermal.

A series of TiO2 supported bimetallic CoMo nitride catalysts were prepared by temperature- programmed reduction of CoMo/TiO2 oxides with flowing ammonia and characterized by BET and XRD. The reaetivities of the CoMo nitride catalysts in the hydrodeoxygenation （ HDO） of phenol were evaluated. The reaction constants of phenol consumption kinetics were described using pseudo first-order reaction kinetics model. It was confirmed that Co3 MOs N was formed from the nitriding of a CoMoO4precursor pre- pared from Co（NO3 ）2 · 6H20 and （NH4）6MoTO2 ·4H2 but not from the mixture of CoO and MoO3. With the addition of Co, a new bimetallic nitride phase of Co3 MO3 N was produced. The addition of Co had both positive and negative effects on the specific area and HDO reactivity of the catalysts. The reaction rate constants of different catalysts were found with the following order： Co4Mo12 〉 Co6Mo12 〉 Co2Mo12 〉 Co8Mo12〉Co0Mo12〉 thermal.