Porous anodic aluminum oxide（AAO） templates, obtained by anodization of aluminum sheets at relatively high voltages, were used for fabricating branched platinum nanowires which copy the three-dimensional branching s...Porous anodic aluminum oxide（AAO） templates, obtained by anodization of aluminum sheets at relatively high voltages, were used for fabricating branched platinum nanowires which copy the three-dimensional branching structure of the nanochannels in the template. The formation of these branched nanochannels is the characteristic of AAO templates grown at 60 V in 0.15 mol/L H2C2O4 solution. When AAO templates are grown at 40 V or lower, straight channels and platinum nanowires are obtained. Platinum nanowires array was alter-current（AC）-electrodeposited in AAO at a lower frequency（20 Hz） and increasing voltage（5-15 V）. Compared with traditional AC electrodeposition condition, the deposition rate of platinum nanowires under this condition is slower and more controllable. Therefore, the platinum nanowires can perfectly copy the structure of the template. The as-obtained Al/AAO/Pt composite and branched platinum nanowires were characterized by X-ray diffraction（XRD） and transmission electron microscope（TEM）, respectively.展开更多
文摘Porous anodic aluminum oxide（AAO） templates, obtained by anodization of aluminum sheets at relatively high voltages, were used for fabricating branched platinum nanowires which copy the three-dimensional branching structure of the nanochannels in the template. The formation of these branched nanochannels is the characteristic of AAO templates grown at 60 V in 0.15 mol/L H2C2O4 solution. When AAO templates are grown at 40 V or lower, straight channels and platinum nanowires are obtained. Platinum nanowires array was alter-current（AC）-electrodeposited in AAO at a lower frequency（20 Hz） and increasing voltage（5-15 V）. Compared with traditional AC electrodeposition condition, the deposition rate of platinum nanowires under this condition is slower and more controllable. Therefore, the platinum nanowires can perfectly copy the structure of the template. The as-obtained Al/AAO/Pt composite and branched platinum nanowires were characterized by X-ray diffraction（XRD） and transmission electron microscope（TEM）, respectively.
文摘为了减少Pt催化剂在燃料电池催化过程中的使用量、增加其催化活性,选择储量丰富、成本低廉的过渡金属Ni与Pt复合,通过交替改变电沉积过程中的沉积电压,在多孔阳极氧化铝(porous anodic alumina,PAA)模板内制备NiPt/Pt多层纳米线阵列。利用扫描电子显微镜(scanning electron microscope,SEM)、透射电子显微镜(transmission electron microscope,TEM)和X射线衍射(X-ray diffraction,XRD)仪等对样品的形貌及结构进行剖析,用电化学工作站对其电催化甲醇、甲酸的性能进行研究。结果表明,NiPt/Pt多层纳米线阵列中,Pt片段和NiPt片段呈周期性排布,催化甲醇和甲酸时最大氧化电流分别为50.2 mA/cm^(2)和102.0 mA/cm^(2),比单质Pt纳米线展现出更强的催化活性,这种增强的催化活性可能源于多层结构导致的较多Pt催化活性位点及Ni、Pt金属间的协同催化作用。
