TiSi复合氧化物性质对NiMo基催化剂加氢脱氧性能的影响

分别以机械混合法与溶胶凝胶法所得的钛硅氧化物TiO_2SiO_2与TiO_2-SiO_2为载体制备了NiMo基催化剂,以含20%小桐子油的正辛烷溶液为原料,在连续流动固定床反应器中考察了催化剂的加氢脱氧性能,并采用X射线衍射(XRD)、氮气物理吸附(BET)、扫描电镜(SEM)和NH3程序升温脱附(NH_3-TPD)等技术对催化剂和TiSi复合氧化物载体进行了表征。结果表明,与TiO_2-SiO_2相比,机械混合法制得的TiO_2SiO_2具有双介孔结构特征、较规则的表面形貌和较多的L酸性中心;溶胶凝胶法制得的TiO_2-SiO_2的表面形貌规则性则较差,负载Ni、Mo的孔道堵塞导致所得催化剂的比表面积和孔容急剧减小,在高温反应条件下TiO_2-SiO_2中的Ti—OH—Si键结构形成的B酸中心对催化剂HDO性能的促进作用较小。催化剂性能的评价结果表明NiMo/TiO_2SiO_2催化剂的加氢脱氧活性优于NiMo/TiO_2-SiO_2催化剂的加氢脱氧性能。

Effect of the Properties of TiSi Composite Oxide on the Hydrodeoxygenation Performance of the NiMo Based Catalyst

NiMo based catalysts were prepared by using TiO2SiO2 and TiO2-SiO2 composites as the support by mechanical mixing method and sol-gel method respectively.The hydrodeoxygenation (HDO) performance of the catalysts were investigated in a continuous flow fixed-bed reactor using the n-octane solution containing 20％(vol) jatropha curcas oil as the raw material.The catalysts and TiSi composite oxide support were characterized by X-ray diffraction (XRD),nitrogen physical adsorption (BET),SEM and NH3 program temperature desorption (NH3-TPD).The results showed that compared with the YiO2-SiO2 prepared by sol-gel method,the TiO2SiO2 prepared by mechanical mixing method has the characteristics of dual mesoporous structure,regular surface morphology and more L-acid centers,while the regularity of the surface morphology of the TiO2-SiO2 prepared by sol-gel method is poor and the drastically decrease of the specific surface area and pore capacity of the NiMo/TiO2-SiO2 catalyst were resulted from the pore-blockage by the loaded Ni and Mo.The B-acid center formed from Ti-OH-Si bond structure in TiO2-SiO2 has little effect on the HDO performance of the catalyst under high reaction temperature.The evaluation results of the catalytic performance of the catalysts indicated that the hydrodeoxygenation activity of NiMo/TiO2SiO2 catalyst is higher than that of NiMo/TiO2-SiO2 catalyst.