摘要
采用TPR,热磁分析,化学吸附,电镜,红外光谱和XPS等手段,详细地研究了催化剂中铂镓的相互作用及Ga的调变机理。结果表明,铂促进了镓的还原,在还原态催化剂中Ga以低价形式存在,且Ga的存在降低了铂簇团的缺电子程度,尽管如此,Ga的引人对Pt簇团的大小无明显的影响,但红外光谱指出,Ga抑制了正己烷在金属簇团上的多位吸附,因此,可以认为Ga与Pt之间主要是电子相互作用。
The interaction between Pt and Ga and the modification role of Ga were investigated by temperature-programmed reduction, thermo-magne-tic analysis, H2 chemisorption, TEM, IR and XPS. The results showed that Pt promoted the reduction of Ga, but Ga could not be reduced to the zero valent state at 450℃. The presence of Ga reduced the electron deficient state of Pt clusters but had no significant effect on its crystal size. Futhermore, the addition of Ga suppressed the multiple adsorption of n-hexane on the catalyst. In addition to its effect on the acidity of the support, the role of Ga could be attributed to the electronic interaction between Pt clusters and low valent Ga ions.
