纳米Ni(OH)2/Ni-Ti-O 纳米管阵列复合电极的制备及其对甲醇的催化氧化性能

Ni-Ti-O Nanotube Arrays Supported Nano-Ni(OH)2 Electrode for Electrocatalytic Oxidation of Methanol

摘要:

阳极氧化NiTi合金板获得了Ni-Ti-O 纳米管阵列（NTOs），并将其加热至500℃在氢气气氛中还原处理2h。采用简单的溶盐浸渍法，将Ni(OH)2纳米颗粒负载在NTOs上制备Ni(OH)2/NTOs/NiTi复合电极。采用场发射扫描电子显微镜（FESEM），X射线光电子能谱（XPS）和循环伏安法（CV）表征电极的表面形貌、电极表面的元素价态和其对甲醇氧化的电催化性能。研究了不同浸渍时间和Ni源浓度等工艺参数对电极微观形貌和电催化氧化性能的影响。结果表明：随着浸渍时间的延长和Ni源浓度的增加，电极上负载的催化纳米颗粒尺寸逐渐增大，氧化峰电流密度先增后降。在25oC时，将NTOs依次浸渍在0.2M NiCl2?6H2O乙醇溶液和0.2M NH4OH乙醇溶液中各12h后，可得到电催化性能良好的纳米Ni(OH)2/NTOs电极，氧化峰电流达到38.41 mA?cm-2。经1000次循环后，电极峰电流密度为原来的75%，表明纳米Ni(OH)2/NTOs电极有良好的循环稳定性，可成为有前景的DMFC的阳极电极候选材料。

Abstract:

Ni-Ti-O nanotube arrays (NTOs) were fabricated by the anodized Ni-Ti alloy and then annealed under hydrogen atmosphere at 500oC for 2hours. The Ni(OH)2/NTOs electrodes were prepared by a convenient impregnating method. The FESEM, XPS and CV will be used to characterize the microstructure, surface electronic states and catalytic performance of Ni(OH)2/NTOs. The effect of the process factors such as impregnation time and concentration of Ni2+ on catalytic activity were investigated. The results show that with prolonging impregnation time and increasing concentration of Ni2+, the catalsty partical size gradually increase and the peak current denstiny firstly increase and then decrese. When the Ni-Ti-O NTs is impregnated in 0.2M NiCl2?6H2O ethanol solution and 0.2M NH4OH ethanol solution 12h in sequence at 25oC,the resulting sample has the best catalytic performance and its peak current density is 38.41 mA?cm-2. Meanwhile, the peak current density of Ni(OH)2/NTOs remain 75% of original value after a consecutive sweep for 1000 times, indicating the excellent lcyclic stability. The Ni(OH)2/NTOs should a promising electrocatalytic electrode for direct methanol fuel cells.