负载Pd纳米粒子聚合物颗粒的制备及其催化性能研究

摘要

Poly（N-vinylacetamide）（PNVA） grafted polyacrylonitrile/polystyrene（PNVA-g-PAN/PSt） polymer spheres were prepared by dispersion copolymerization of acrylonitrile（AN）,styrene（St）,and PNVA macromonomer using AIBN as an initiator.Palladium nanoparticles were homogenously located onto surfaces of the PNVA-g-PAN/PSt polymer spheres,which was confirmed by transmission electron microscopy（TEM）,by reduction method using PdCl2 as metal and ethanol as reducing agent.The amorphous diffraction peak of the polymeric particles and obvious palladium cubic crystal diffraction peaks were appeared in the powder of X-ray diffraction（XRD） pattern.The diameter of palladium nanoparticles,calculated from the XRD,was about 9nm.Moreover,the weight percentages of palladium nanoparticles stabilized onto the microspheres were about 15 to 30,which were calculated from the thermogravimetric analysis（TGA）.Glucose could convert to sodium gluconate easily in the present of the pd@PNVA-g-PAN/PSt spheres,suggesting the nanoparticles had excellent catalytic oxidization.%使聚N-乙烯基乙酰胺（PNVA）大分子单体与苯乙烯（St）和丙烯腈（AN）进行三元分散共聚,制得了粒径分布较均一、表面带有花纹状的PNVA-g-PAN/PSt聚合物颗粒,进而以PdCl2为金属源,乙醇为还原剂,采用醇热法将Pd2＋离子还原成Pd纳米粒子并负载于聚合物颗粒表面。透射电子显微镜（TEM）观察表明Pd纳米粒子在聚合物颗粒表面且分布均匀。X射线衍射（XRD）花样图显示Pd纳米粒子为立方晶系,其粒径在9nm左右。热重分析（TGA）结果表明PNVA-g-PAN/PSt聚合物颗粒表面所含Pd纳米粒子的质量分数为0.15%～0.30%。在Pd纳米粒子存在的条件下,可使葡萄糖容易转化为葡萄糖酸,表明该负载型Pd纳米粒子具有良好的催化氧化作用。