Superficial characterization and hydroconversion of tetralin over NiW sulfide catalysts supported on zirconium doped mesoporous silica

摘要

The influence of the W/Ni ratio and the phosphorous content as a promoter in the catalytic performance of NiW sulfide supported on zirconium containing mesoporous silica in the hydroconversion of tetralin has been studied.Three catalysts with a W loading of 20 wt.% and Ni loading of 2.5,5 and 7.5 wt.% were prepared.To study the effect of phosphorous as promoter,prior to the metallic impregnation,0.5,1.5,3.0 and 5.0 wt.% of P_2O_5 was incorporated to the support.The catalysts were sulfided with a H_2/H_2S mixture at 400 C for 2 h,and finally tested in the hydrogenation (HYD)/ring-opening of tetralin at 6.0MPa (4.5 MPa H_2 and 1.5MPa N_2).Using IR and XP spectroscopies,a correlation has been established between the catalytic performance and the dispersion and type of compounds formed on the support.The formation of a highly dispersed NiWO_4 phase,easily sulfidable,and the high acidity of mild strength of the catalysts,could explain the good catalytic performance observed.The catalyst with 5 wt.% of Ni,20 wt.% of W and 0.5 wt.% of P_2C>5 shows an excellent catalytic performance and is higher than that observed with a sulfided commercial Ni-Mo/Al_2O_3,in the same experimental conditions.