ZnFe2O4 hollow spheres (ZFHs) with sizes of 200-302 nm were synthesized by simple impregnating method using the as-prepared phenolic formaldehyde (PF) spheres as templates and subsequent annealing at 500-700 ℃. The p...ZnFe2O4 hollow spheres (ZFHs) with sizes of 200-302 nm were synthesized by simple impregnating method using the as-prepared phenolic formaldehyde (PF) spheres as templates and subsequent annealing at 500-700 ℃. The prepared ZFHs are assembled by a large number of small nanoparticles with sizes of 15-20 nm, and many mesopores exist among these nanoparticles. The samples annealed at 500-550℃ exhibit a single cubic spinel structure, while higher annealing temperature leads to the formation of hexagonal ZnO and rhombohedral α-Fe2O3 secondary phases. The size of the assembled nanoparticles increases with the increase in annealing temperature. Novel magnetic transformation from paramagnetic to ferrimagnetic is induced by the reduction of annealing temperature and the saturation magnetization significantly increases from 2.3 to 13.5 A·m^2/kg. The effect of the formation of hollow sphere structure on the redistribution of Fe^3+ and Zn^2+ in the spinel structure was studied.展开更多
Magnetic yolk-shell structured anatase-based microspheres were fabricated through successive and facile sol-gel coating on magnetite particles, followed by annealing treatments. Upon loading with gold nanoparticles, t...Magnetic yolk-shell structured anatase-based microspheres were fabricated through successive and facile sol-gel coating on magnetite particles, followed by annealing treatments. Upon loading with gold nanoparticles, the obtained functional magnetic microspheres as heterogeneous catalysts showed superior performance in catalyzing the epoxidation of styrene with extraordinary high conversion （89.5%） and selectivity （90.8%） towards styrene oxide. It is believed that the construction process of these fascinating materials features many implications for creating other functional nanocomposites.展开更多
文摘以粒径约为120 nm的Fe_3O_4磁性纳米球为内核,经过SiO_2包埋,BSA修饰并吸附金纳米球三步后得到一种组装型金磁复合纳米球MNP@SiO_2@BSA@AuNPs,并以此纳米球为载体,建立了检测心梗标志物之一的肌红蛋白的新方法.金磁复合纳米球偶联肌红蛋白抗体4E2后,可快速分离和富集样品中的肌红蛋白,加入偶联有肌红蛋白抗体7C3的荧光硅纳米球后形成三明治夹心结构,通过检测荧光强度实现了对肌红蛋白的定量检测.结果表明:该检测方法在肌红蛋白浓度为0~250 ng·m L^(-1)的范围内荧光强度与肌红蛋白浓度具有良好的线性关系(R^2=0.993),选择性高,重复性好,快速检测肌红蛋白时间不超过30 min.
基金Project(51574293)supported by the National Natural Science Foundation of ChinaProject supported by the Independent Research Program of State Key Laboratory of Powder Metallurgy,China
文摘ZnFe2O4 hollow spheres (ZFHs) with sizes of 200-302 nm were synthesized by simple impregnating method using the as-prepared phenolic formaldehyde (PF) spheres as templates and subsequent annealing at 500-700 ℃. The prepared ZFHs are assembled by a large number of small nanoparticles with sizes of 15-20 nm, and many mesopores exist among these nanoparticles. The samples annealed at 500-550℃ exhibit a single cubic spinel structure, while higher annealing temperature leads to the formation of hexagonal ZnO and rhombohedral α-Fe2O3 secondary phases. The size of the assembled nanoparticles increases with the increase in annealing temperature. Novel magnetic transformation from paramagnetic to ferrimagnetic is induced by the reduction of annealing temperature and the saturation magnetization significantly increases from 2.3 to 13.5 A·m^2/kg. The effect of the formation of hollow sphere structure on the redistribution of Fe^3+ and Zn^2+ in the spinel structure was studied.
文摘Magnetic yolk-shell structured anatase-based microspheres were fabricated through successive and facile sol-gel coating on magnetite particles, followed by annealing treatments. Upon loading with gold nanoparticles, the obtained functional magnetic microspheres as heterogeneous catalysts showed superior performance in catalyzing the epoxidation of styrene with extraordinary high conversion （89.5%） and selectivity （90.8%） towards styrene oxide. It is believed that the construction process of these fascinating materials features many implications for creating other functional nanocomposites.
