NiFe双金属催化剂用于月桂酸甲酯加氢的研究

负载型Ni Fe/γ-Al_2O_3双金属催化剂的物理化学性质明显受还原温度的影响,进而影响月桂酸甲酯的加氢活性和产物选择性。金属Ni活性中心主要促进脱羰/脱羧(DOC)反应,Fe的加入能促进月桂酸甲酯发生加氢脱氧反应,促进C_(12)烷烃化合物生成。H_2-TPR、XRD、H_2-TPD和BET结果表明,高的还原温度有利于金属或合金活性中心形成,NiFe双金属催化剂的加氢活性取决于金属Ni、Fe和NiFe合金的含量;NiFe双金属催化剂吸附与活化H_2分子的能力明显受还原温度的影响。在研究的温度范围内,Ni活性中心具有优异的加氢和裂解性能,Fe物种的引入能有效抑制裂解性能。双金属催化剂的加氢活性顺序:NF420NF360NF450NF300,在420℃下经H_2还原制得的NF420催化剂具有最佳的月桂酸甲酯加氢性能,在反应温度为380℃时,月桂酸甲酯加氢转化率和烷烃化合物选择性分别高达93.3%和90.0%。

Study of bimetallic NiFe catalysts for methyl laurate hydrogenation

The physicochemical properties of the prepared bimetallic NiFe/γ-Al₂O₃ catalysts can be affected by reduction temperature, which can change the hydrogenation activity and product selectivity for methyl laurate catalytic hydrogenation. The metal Ni active sites mainly promote the decarbonylation/decarboxylation (DCO/DCO₂) reaction, and the addition of Fe can promote the hydrodeoxygenation (HDO) reaction of methyl laurate to produce C₁₂ alkanes. The results of H₂-TPR, XRD, H₂-TPD and BET indicate that high reduction temperature is beneficial to the formation of metal or alloy active centers. The hydrogenation activity of bimetallic catalysts depends on the content of metal Ni, Fe and NiFe alloy. The ability of NiFe bimetallic catalyst to adsorb and activate H₂ is obviously affected by reduction temperature. In the studied temperature range, Ni active centers have excellent hydrogenation and cracking performances, and the introduction of Fe species can effectively inhibit the cracking performance. The sequence of catalytic hydrogenation activity for these bimetallic catalysts is:NF420 > NF360 > NF450 > NF300. When the reduction temperature is 420℃, the prepared NF420 catalyst owns the best catalytic hydrogenation performances. The conversion of methyl laurate and the selectivity of alkanes are 93.3% and 90.0% at the reaction temperature of 380℃, respectively.