层状双金属氢氧化物加氢精制催化剂研究进展

Research progress of layered double hydroxides-based hydrotreating catalysts

层状双金属氢氧化物(LDHs)型加氢精制催化剂的制备可通过原位合成路线,将含W或Mo的阴离子引入层间,将Ni或Co引入层板;也可通过负载型路线,将LDHs焙烧后的复合金属氧化物作为载体负载活性组分。LDHs对加氢性能产生的有利影响主要来自四个方面,一是实现活性组分高负载量下的高分散;二是促进Ni(Co)-Mo(W)-S活性相形成;三是生成堆积层数更高更弯曲的活性相;四是调变催化剂的酸碱性。LDHs型加氢精制催化剂具有优异的脱除位阻硫化物、芳环加氢和催化裂化汽油选择性加氢脱硫性能。深入研究LDHs构效关系并探索它在免预硫化催化剂中的新应用是未来的研究方向。

Hydrotreating catalysts based on layered double hydroxides(LDHs)are mostly prepared by two ways.One is in situ synthesis route,incorporating Ni and/or Co into the layers and intercalating tungstate and/or molybdate into the interlayer followed by calcination and sulfidation.The other is supported route,impregnating active metal salts onto layered double oxides obtained by calcining LDHs at certain temperatures.The beneficial effects of LDHs on hydrotreating performance mainly originate from four aspects.First,highly dispersed active metals are achieved under high metal loadings.Second,the intimate contact between metals in the layers and interlayer could promote the formation of Ni(Co)-Mo(W)-S active phases.Third,more stacked and curved active phases can be formed.Fourth,the acidity and basicity of catalysts are tunable.Therefore,LDHs-based catalysts show superior performances for hydrodesulfurization(HDS)of sterically hindered sulfides,hydrodearomatization and selective HDS of fluid catalytic cracking gasoline.Further attention might be focused on comprehensively understanding the structure-activity relationship of LDHs and developing their new application in pre-sulfided hydrotreating catalysts.