一步法制备纳米层状钒磷氧催化剂

以多聚磷酸为替代磷源、硝酸铋和二甲基亚砜为助剂,采用一步法制备了纳米层状钒磷氧(VPO)催化剂,采用XRD,SEM,XPS,FTIR,BET等方法对纳米层状VPO催化剂进行了表征,并对其催化正丁烷氧化制顺酐反应的性能进行了评价。表征结果显示,纳米层状VPO、催化剂的微观形貌呈玫瑰花苞状,花苞是由大量片层晶体堆积而成,花苞直径约为5～7μm,片层晶体厚度约为50～80nm;催化剂表面成分主要是(VO)_2P_2O_7。实验结果表明,纳米层状VPO催化剂的催化性能良好,在正丁烷与空气体积比1.5:98.5、气态空速1500 h~(-1)、反应温度400℃、反应时间72h的条件下,正丁烷转化率为79.4%,顺酐选择性为68.8%,顺酐收率为54.63%。

Preparation of Nano-Layered VPO Catalyst by One-Step Method

The nano-layered VPO catalyst which was used in the selective oxidation of n-butane to maleic anhydride was prepared by one-step method with polyphosphoric acid as phosphorous source, and Bi(NO_3)_3·5H_2O and dimethyl sulfoxide as promoters.The catalyst and its precursor were characterized by means of XRD,SEM,XPS,FTIR and BET.The results showed that the VPO catalyst displayed the"flattened-rose"type morphology with 5-7μm in diameter which formed by a lot of close stacked lamellar crystals with 50-80 nm in thickness.(VO)_2P_2O_7 is the active phase on the catalyst surface.Under the conditions of V(n-butane):V(air)1.5:98.5,GHSV 1 500 h~(-1),400℃ and 72 h,the conversion of n-butane was 79.4%,and the selectivity and yield to maleic anhydride were 54.63% and 68.8%,respectively.