负载纳米银复合微球制备及其催化性能

以具有温度和pH双重敏感性能的N-异丙基丙烯酰胺(NIPAM)共聚丙烯酸(AA) P(NIPAM-co-AA)高分子微凝胶为模板, 以乙醇为还原剂, 原位还原得到负载纳米银的微米尺度Ag/P(NIPAM-co-AA)复合微凝胶材料. 通过扫描电子显微镜(SEM)、X射线衍射(XRD)仪和紫外-可见(UV-Vis)分光光度计等对复合材料的形貌、组成和催化性能进行表征. 研究结果表明, Ag/P(NIPAM-co-AA)复合微球具有均一的表面结构, 微凝胶的限域作用显著提高了纳米银的分散性和稳定性. 另外, Ag/P(NIPAM-co-AA)复合微球对对硝基苯酚(4-NP)的还原具有较好的催化活性, 且其催化活性与微凝胶网络结构的溶胀、收缩行为有一定关系, 即模板微凝胶的温敏特性可以实现对对硝基苯酚催化反应活性的调控作用.

Synthesis and Catalytic Activity of Silver Nanoparticles Immobilized onto Composite Microspheres

P(NIPAM-co-AA) copolymer microgels with temperature and pH sensitivities were synthesized by copolymerization of N-isopropylacrylamide (NIPAM) and acrylic acid (AA). Ag/P(NIPAM-co-AA) composite microspheres were prepared via in-situ reduction using ethanol as a reducing agent, based upon a polymer microgel template method. The morphology, composition, and catalytic properties of the prepared composite microspheres were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV-visible (UV-Vis) spectrophotometry. It was demonstrated that the Ag/P(NIPAM-co- AA) composite microspheres had an uneven surface structure. The confinement effect of the template microgels significantly improved the dispersion and stability of the loaded silver particles. In addition, the obtained composite materials exhibited good catalytic activity for the reduction of 4-nitrophenol (4-NP). The observed catalytic activity was related to the swelling and shrinking behavior of the microgel network structure. The catalysis of 4-nitrophenol reduction was controlled by adjusting the thermo-sensitivity of the polymer template.