Abstract:

La-Ni-Mo-B amorphous catalyst was prepared by chemical reduction of ammonium heptamolydate，nickel nitrate and lanthanum nitrate with sodium borohydride aqueous solution. The hydrodeoxygenation（HDO）performance was tested using phenol as a model compound. Results showed that the amorphous catalyst exhibited high HDO activity，but the phenol conversion was decreased to 58.5% when the reaction temperature was increased to 548 K. The deactivation was mainly attributed to the serious agglomeration of catalyst particles，the significant reduction in specific surface area，the transformation of Ni active site from amorphous structure to crystalline structure and the decrease in electron transfer under the condition of temperature 548 K. The hydrogenation activity of the catalyst was inhibited and then the reaction route proceeded with the direct deoxygenation route，which lead to the phenol conversion decreased to 37.5% and aromatic benzene content increased to 22.3% at the temperature 523 K over La-Ni-Mo-B（C）.

摘要：

以(NH₄)₆Mo₂₄、Ni(NO₃)₂和La(NO₃)₃为原料，NaBH₄为还原剂，采用化学还原法制备出非晶态催化剂La-Ni-Mo-B，以苯酚为模型化合物研究其加氢脱氧性能。结果表明，非晶态催化剂具有较高的加氢脱氧活性，而在548 K时苯酚转化率降低至58.5%。主要原因是该非晶态催化剂在548 K下，颗粒发生明显团聚，比表面积显著下降，非晶态Ni活性中心发生晶化，电子转移减少，抑制了催化剂的加氢活性，使反应路径偏向直接脱氧的方式进行，从而导致经过高温热处理的La-Ni-Mo-B（C）在523 K时，苯酚转化率下降至37.5%，芳香烃苯的含量增加至22.3%。