Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.
ACS Nano. 2010 Mar 23;4(3):1732-8. doi: 10.1021/nn901879d.
Solid nanotubes comprising alpha-Fe2O3 nanoparticles were prepared from iron-storage protein ferritin. Their structure, magnetic properties, and photocatalytic activities were characterized. The initial ferritin nanotube precursors were fabricated using alternating layer-by-layer depositions of poly-L-arginine (PLA) and ferritin into a track-etched polycarbonate membrane (pore diameter, 400 nm) with subsequent dissolution of the template. The obtained uniform cylinders of (PLA/ferritin)3 (outer diameter, 410 +/- 14 nm) were calcinated at 500 degrees C under air, yielding reddish-brown iron oxide nanotubes. The one-dimensional hollow structure remained perfect, but its diameter, wall thickness, and maximum length were markedly diminished. Disappearance of the protein shell and the PLA layers were confirmed using IR and EDX spectroscopy. Subsequent SEM, TEM, and XPS measurements showed that the tubular walls comprise fine alpha-Fe2O3 nanoparticles with a 5 nm diameter. These alpha-Fe2O3 nanotubes demonstrated superparamagnetic properties with a blocking temperature of 37 K and efficient photocatalytic activity for degradation of 4-chlorophenol.
采用层层自组装方法将多聚 L-精氨酸（PLA）和铁蛋白组装到醋酸纤维素膜上，制备了铁蛋白纳米管的前体，随后用溶剂溶解模板得到均匀的（PLA/铁蛋白）3 纳米管（外径为 410 ± 14nm）。将所得纳米管在空气中于 500°C 下煅烧，得到红棕色氧化铁纳米管。一维空心结构保持完整，但直径、壁厚和最大长度明显减小。IR 和 EDX 光谱证实了蛋白质外壳和 PLA 层的消失。随后的 SEM、TEM 和 XPS 测量表明，管壁由 5nm 直径的细小α-Fe2O3 纳米粒子组成。这些α-Fe2O3 纳米管表现出超顺磁性，具有 37 K 的阻塞温度，并具有有效降解 4-氯苯酚的光催化活性。
