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采用等体积浸渍法制备了双金属Ni-W催化剂,并研究了制备过程中前驱体溶液pH值对活性的影响。柠檬酸和氢氧化钾分别作为酸碱调节剂将前驱体溶液pH值调节至0.83、1.00、3.09、5.00、7.03、8.97和11.0。纤维素氢解反应结果表明,当前驱体溶液的pH值为1.00时,在氢压为5.0 MPa、温度为518 K的反应条件下,得到低碳(C_(2,3))多元醇的总收率为74.5%。此外,通过BET和SEM表征了催化剂的物理性质。其比表面积为330-450 m2/g,且在高温煅烧下SBA-15仍保持良好的水热稳定性。TEM和SEM-EDX结果显示,催化剂粒子在载体表面分散性较好,但也有少量的聚集现象。XRD表征表明,NiO等物种的还原程度明显受到pH值的影响,且镍、钨物种的相态也存在着显著不同。
The bimetallic Ni-W catalyst was prepared by the same volume impregnation method and the influence of the pH value of the precursor solution on the activity was studied. The pH of the precursor solution was adjusted to 0.83, 1.00, 3.09, 5.00, 7.03, 8.97 and 11.0 by using citric acid and potassium hydroxide as acid-base regulators, respectively. The results of cellulose hydrogenolysis showed that when the pH of the precursor solution was 1.00, the total content of low carbon (C 2, 3) polyols was obtained under the conditions of a hydrogen pressure of 5.0 MPa and a temperature of 518 K Yield 74.5%. In addition, the physical properties of the catalyst were characterized by BET and SEM. Its specific surface area is 330-450 m2 / g, and SBA-15 maintains good hydrothermal stability under high temperature calcination. The results of TEM and SEM-EDX showed that the catalyst particles dispersed well on the support surface, but there was also a small amount of aggregation. XRD characterization shows that the reduction degree of NiO and other species is obviously affected by pH value, and the phase states of nickel and tungsten species are also significantly different.