以胶原纤维(CF)接枝表棓儿茶素棓酸酯(EGCG)为载体,制备了新型Pd-Ni/CF-EGCG催化剂.EGCG作为"桥分子"对Pd-Ni纳米粒子起着分散和锚定作用.通过热重分析、扫描电镜、透射电镜、X射线光电子能谱和X射线衍射对该催化剂进行了表征.结果表明,该催化剂具有规整的纤维结构,在纤维表面形成了高分散的平均粒径为2.2nm的Pd-Ni合金颗粒.液相硝基苯催化加氢反应结果表明,当Ni和Pd摩尔比为0.8时,Pd-Ni/CF-EGCG催化剂具有最佳的双金属协同作用,在308K和1.0MPa氢压下,加氢速率达237min-1,比单金属的Pd/CF-EGCG快1倍,重复使用5次后仍具有较高的催化活性.
A novel Pd-Ni bimetallic nanoparticle catalyst supported on epigallocatechin-3-gallate (EGCG) grafted collagen fiber (CF),Pd-Ni/CF-EGCG,has been prepared. EGCG was selected as a bridge molecule to anchor Pd-Ni nanoparticles and control the size and distribution of Pd-Ni nanoparticles. The morphology and physical properties of this catalyst were characterized by thermo-gravimetric analysis,scanning electron microscopy,transmission electron microscopy,X-ray photoelectron spectroscopy,and X-ray diffraction. It was observed that this catalyst was in an ordered fibrous state,and well-dispersed Pd-Ni nanoparticles with an average diameter of 2.2 nm formed at the outer surface of CF. Hydrogenation of nitrobenzene catalyzed by Pd-Ni/CF-EGCG was investigated. An optimal synergistic action can be achieved when the molar ratio of Ni/Pd was 0.8,and the turnover frequency (TOF) was 237 min-1 at 308 K and 1.0 MPa,which is twice as high as that of Pd/CF-EGCG. Pd-Ni/CF-EGCG still has higher activity after reuse five times.