Mo对非晶态合金Ni-B/TiO_2-Al_2O_3催化糠醛液相加氢的影响

采用浸渍法制备了TiO2-Al2O3复合载体,并采用浸渍还原法制备了非晶态合金Ni-B/TiO2-Al2O3催化剂;以糠醛液相加氢为探针反应,采用示差扫描量热法、比表面积测试、程序升温还原和程序升温脱附等表征手段,考察了Mo对Ni-B/TiO2-Al2O3催化剂性能的影响。研究结果表明,Mo的添加显著提高了Ni-B/TiO2-Al2O3催化剂的活性和糠醇的选择性,当Mo质量分数为0.675%~1.250%时,糠醛转化率和糠醇选择性均达到100%;Mo能提高Ni-B/TiO2-Al2O3催化剂的热稳定性,部分氧化态物种易于还原,同时催化剂的吸氢强度减弱,化学吸附中心数增加,显著提高催化剂的活性。Mo的适量添加使产物糠醇在催化剂上易于脱附,防止其深度加氢,提高了糠醇的选择性。

Effect of Mo in Amorphous Alloy Ni-B/TiO2-Al2O3 as Catalyst for Liquid-Phase Hydrogenation of Furfural

TiO2-Al2O3 composite support was prepared by impregnation.Ni-B/TiO2-Al2O3 amorphous alloy catalyst was prepared by impregnation-reduction.The liquid phase hydrogenation of furfural to furfural alcohol as probe reaction was carried out on the catalyst.Effects of Mo on catalytic properties of Ni-B/TiO2-Al2O3 were studied by means of DSC,BET,TPR and TPD.Ni-B-Mo/TiO2-Al2O3 amorphous alloy catalyst showed high activity and selectivity for the liquid phase hydrogenation.When mass fraction of Mo to TiO2-Al2O3 is in range of 0.675%-1.250%,both activity and selectivity of catalyst are 100%.Mo can also improve thermal stability of Ni-B/TiO2-Al2O3.TPR and TPD measurements indicate that addition of Mo can facilitate reduction of Ni,weaken strength of Ni—H bonds and increase adsorption centers,therefore promote catalyst activity.Mo can on the other hand make desorption of furfural alcohol from surface of catalyst easier.So selectivity of catalyst to furfural alcohol is improved.