采用化学沉淀法合成了SiO2-ZrO2复合氧化物载体,并以浸渍法制备了Ni/SiO2-ZrO2双功能催化剂,考察了焙烧温度对催化剂结构及其催化愈创木酚加氢脱氧制环己烷性能的影响.结果表明,经500℃焙烧催化剂的加氢脱氧活性最高,在Ni金属中心和SiO2-ZrO2载体材料的协同作用下,愈创木酚转化率为100%,环己烷选择性为96.8%.对催化剂进行N2物理吸附、H2化学吸附、X射线衍射分析、H2程序升温还原、NH3程序升温脱附与Raman光谱等表征后发现,合成的SiO2-ZrO2为无定形的酸碱两性氧化物;经500℃焙烧的催化剂样品的有效比表面积和孔体积均明显增大,表面酸量最多,硝酸镍分解成小颗粒的NiO较易被H2还原,这些特性是该催化剂样品具有高效加氢脱氧活性的原因.
SiO2-ZrO2 composites were synthesized by chemical precipitation and used to prepare a series of bifunctional Ni/SiO2-ZrO2 catalysts by impregnation. The effect of calcination temperature on the catalyst structure and its catalysis of the hydrodeoxygenation of guaiacol was investigated. Guaiacol was converted to cyclohexane by a synergism between the metal center and solid acid support. The catalyst calcined at 500 ℃ gave a maximum 100% guaiacol conversion and 96.8% selectivity for cyclohexane. The catalyst samples were characterized by N2 adsorption, H2 chemisorption, X-ray diffraction, H2 temperature-programmed reduction, NH3 temperature-programmed desorption, and Raman spectroscopy. The synthesized SiO2-ZrO2 was an amorphous oxide. The Ni/SiO2-ZrO2 catalyst calcined at 500 ℃ has more acidity, smaller NiO particles, and larger BET surface area and pore volume, which gave it the best catalytic performance.