A series of Ni/SBA-15 catalysts were prepared by impregnation method for the hydrogenation of levulinic acid (LA) to γ-valerolactone in a fixed bed reactor at atmospheric pressure. The catalysts were characterized by XRD, TPR, AAS, Pulse chemisorption, SEM-EDAX, TEM, BET Surface area and XPS. The catalyst 30 wt% Ni/SBA-15 exhibited excellent catalytic performance (97% yield) at 250 °C due to the presence of superior number of active surface Ni species. While 30 wt% Ni/SiO₂ catalyst showed lower catalytic activity (87% yield) at about similar conversion. The co-feeding of formic acid (FA) and water (impurities) with levulinic acid was also evaluated over 30 wt% Ni/SBA-15 which yielded excellent levulinic acid conversion. The noteworthy results were obtained at a molar ratio of FA/LA = 5. The constant catalytic activity during 10 h experiment with an external H₂ flow has showed the sturdiness of the Ni/SBA-15 catalyst. On the other hand, a slight decrease in conversion as well as yield during the time-on-stream in the absence of external H₂ flow was attributed to the accumulation of carbon species on the catalyst surface.

中文翻译：

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Ni / SBA-15催化剂上有或没有外部氢的乙酰丙酸加氢

通过浸渍法制备了一系列Ni / SBA-15催化剂，用于在大气压下在固定床反应器中将乙酰丙酸（LA）加氢成γ-戊内酯。通过XRD，TPR，AAS，脉冲化学吸附，SEM-EDAX，TEM，BET表面积和XPS对催化剂进行了表征。30wt％的Ni / SBA-15催化剂在250℃下表现出优异的催化性能（97％收率），这是由于存在大量的活性表面Ni物质。而30 wt％Ni / SiO ₂在大约相似的转化率下，催化剂显示出较低的催化活性（87％的收率）。还在超过30 wt％的Ni / SBA-15上评估了甲酸（FA）和水（杂质）与乙酰丙酸的共进料，产生了优异的乙酰丙酸转化率。在FA / LA = 5的摩尔比下获得了值得注意的结果。在外部H ₂流动的10 h实验中，恒定的催化活性显示了Ni / SBA-15催化剂的坚固性。另一方面，在没有外部H ₂流动的情况下，在运行时间中转化率和产率的略微下降归因于碳物质在催化剂表面上的积累。