猝冷速度对骨架Ni催化剂结构和催化性能的影响

来源 :高等学校化学学报 | 被引量 : 0次 | 上传用户:wangtan2
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在5种不同猝冷速度下制备Ni-Al合金,然后以碱处理并活化得到多孔猝冷骨架Ni催化剂.通过电感耦合等离子发射光谱(ICP)、X射线粉末衍射(XRD)、H2-程序升温脱附(H2-TPD)和氮物理吸附等方法对催化剂的物理化学性质进行了表征.结果发现,随着冷却速度的增加,活化后的催化剂具有更多的残余Ni2Al3相、更低的比表面积、更大的孔容和孔径、更小的Ni晶粒、更大的Ni-Ni间距和更加单一的活性位.另外,还发现在肉桂醛选择加氢反应中,冷却速度的提高也促进了催化剂的活性和对目标产物3-苯丙醛选择性的提高.以RQNi5为催化剂,加氢产物3-苯丙醛的收率达到88.8%,转化率为98.4%,明显优于工业上广泛使用的RaneyNi催化剂.同时,对猝冷骨架Ni催化剂的结构与催化性能之间的关系进行了讨论. The Ni-Al alloy was prepared at five different quenching rates and then treated with alkali to activate the porous Ni catalyst.The results of ICP-AES, XRD, (H2-TPD) and physical adsorption of nitrogen were used to characterize the physicochemical properties of the catalyst. The results showed that the activated catalyst had more residual Ni2Al3 phase with the increase of cooling rate, and the lower specific surface area , Larger pore volume and pore size, smaller Ni grains, larger Ni-Ni spacing and more single active sites.In addition, it was also found that in the selective hydrogenation of cinnamaldehyde, the increase of the cooling rate is also promoted Catalyst activity and selectivity to 3-phenylpropionaldehyde.With RQNi5 as catalyst, the yield of 3-phenylpropionaldehyde was 88.8% and the conversion rate was 98.4%, which was obviously superior to that of the commercial one Of RaneyNi catalyst.At the same time, the relationship between the structure and catalytic performance of Ni catalyst with quenched framework was discussed.
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