负载型Pd-B非晶态合金催化剂用于TCPD加氢的研究

Study on the Synthesis and Hydrogenation Activity of Supported Pd-B Amorphous Alloy Hydrogenation Catalyst

非晶态合金因具有独特的短程有序、长程无序结构而表现出了优良的催化性能。今采用化学还原法以KBH4为还原剂制备得到负载型Pd-B/γ-Al2O3非晶态合金催化剂,并对其结构进行定性检测。催化剂的XRD、SEM结构表征结果表明,负载所得催化剂活性中心Pd为非晶态结构。以三环戊二烯(TCPD)加氢生成四氢三环戊二烯(THTCPD)为探针反应,研究结果表明新鲜非晶态催化剂活性优于常规H2还原所得负载型Pd/γ-Al2O3催化剂。热处理后的非晶态催化剂XRD、SEM分析结果表明其非晶结构受到破坏,活性中心晶化、团聚、分散度降低导致催化活性降低,且温度越高Pd晶化度越深。热处理温度低于150°C条件下催化剂结构基本保持稳定,600°C热处理2h后所负载活性中心完全晶化。

The Pd-B/γ-Al2O3 amorphous alloy catalyst was prepared by routine impregnation and chemical reduction with borohydride in aqueous solution, and its amorphous structure was confirmed by XRD and SEM. The hydrogenation process of tricyclopentadiene （TCPD） to form tetrahydrotricyclopentadient （THTCPD） was used as a probe test to measure the activity of the prepared Pd-B/γ-Al2O3 amorphous alloy catalyst and the measured activity was compared with the activity of the Pd/γ-Al2O3 catalyst prepared by conventional H2 reduction. Results show that the prepared amorphous catalyst has a higher catalytic activity than that of Pd /γ-Al2O3 catalyst, and the catalytic activity of amorphous alloy is affected by the calcination temperature, which decreases rapidly with the increase of calcination temperature. According to XRD and SEM, it may be concluded that the effect of calcination temperature on the catalytic activity can be attributed to the surface structure changes which are caused by the transformation of amorphous structure to crystalline structure. Results also show that the catalyst structure remains well if the temperature of thermal treatment is lower than 150℃, and if the treating temperature is 600℃, the loaded activity centers of the catalyst will be totally crystallized after 2 h of thermal treatment.