炭载体对Pt-C复合物非碱性条件下催化甘油氧化性能的影响

摘要

Activated carbon (AC) and carbon nanotubes (CNTs) supported Pt catalysts with similar particle sizes prepared by incipient wetness impregnation method were used for study of base-free oxidation of glycerol. The results showed that carbon support of Pt-C composite catalysts had significant impact on reactivity, selectivity, and steady state of glycerol oxidation. Compared to Pt/CNTs catalyst, Pt/AC catalyst had a lower binding energy of Pt 4f leading to a higher oxygen coverage on catalyst surface which reduced glycerol adsorption and initial activity of glycerol oxidation. Pt/AC catalyst further favored oxidation of glyceraldehyde to glyceric acid and C—C bond cleavage of C3 products. With regards to catalyst deactivation, oxygen poison and adsorption of intermediates were main factors to Pt/AC catalyst while blockage of Pt active sites by adsorption of glyceric acid was a significant contributor to Pt/CNTs catalyst.%采用等量浸渍法制备了具有相似平均粒径的活性炭（AC）和碳纳米管（CNTs）负载的Pt催化剂，并比较研究了非碱性条件下两种催化剂催化甘油氧化反应的性能。结果表明，炭载体对Pt-C复合物催化甘油氧化反应的活性、选择性和稳定性有重要影响。相对于Pt/CNTs催化剂，Pt/AC催化剂中Pt 4f结合能较低，导致其表面氧的覆盖度相对较高，因而抑制了甘油的吸附，降低了甘油氧化反应的初始活性；Pt/AC 催化剂会促进甘油醛进一步氧化成甘油酸以及C3产物的氧化断键；Pt/AC催化剂失活的主要原因是氧中毒和中间产物的吸附，而Pt/CNTs催化剂的失活主要是由于甘油酸的吸附堵塞Pt表面的活性位造成的。