Development of nano-scale porous and non-equilibrium materials by chemical dealloying process and application for catalyst

在化学脱合金法合成细小骨架银的过程中，银在铝相中的溶解度对产率影响的报道很少。在Al-Ag二元合金体系中，溶解度随温度变化较大。在本工作中，制备了一些不同溶解度的前驱体，并对它们进行了化学脱合金化。在Ar气氛中熔化不同成分的合金，然后用旋转水雾化工艺进行快速凝固。得到的雾化颗粒的平均直径约为200μm，平均冷却速率为104~105K/S。一种是溶解度最高的溶液处理，另一种是溶解度最小的沉淀处理。这两种治疗方法都被归类为固态手术。另一方面，快速凝固被归类为液体操作(Liquid…三种不同溶解度的前驱体进行了脱合金化。在快速凝固前驱体的情况下，它几乎是α相的单一相。固溶处理后，在固溶温度下水淬析出大量的Ag2Al相，由于析出速率较高，在淬火过程中难以抑制Ag2Al相的析出。沉淀处理后，其溶解度可忽略不计。通过化学脱合金化，α相中的Ag生成了细小的骨架Ag，没有Ag2Al相的分解形成骨架Ag。快速凝固是提高骨架银生产效率的有效方法，添加的银中约有80%以骨架银的形式被回收。另一方面，在其他两个先兆中。回收率相当低，不到10%。前驱体制备的快速固化根部相当优良。所得骨架银对2H_2O_2、→、2H_2O+O_2具有较高的分解活性，在其他反应中表现出较高的活性。较少

There was few reports on the effect of the solubility of Ag in the Al phase on the productivity in synthesize of the fine skeletal Ag by the chemical dealloying process. In Al-Ag binary alloy system, the *olubility widely changes with temperature. In this work, some precursors with different solubility were prepared and they were chemically dealloyed. The alloys with various composition were melt in Ar atmosphere and then were rapidly solidified by the rotating-water atomization process. Thus atomized particles were obtained and their mean diameter was about 200μm. The mean cooling rate of the particles was estimated in the range of 10^4-10^5K/s. To control the solubility, two kinds of heat treatments were carried out. One of them was solution treatment for the highest solubility and the other was precipitation treatment for the minimum solubility. Both treatments were classified to a solid state operation. On the other hand, the rapid solidification was classified to a liquid operatio … More n. Three kinds of precursors wuth different solubility were dealloyed. In the case of the rapidly solidified precursor, it was almost a mono phase of the α phase. After the solution treatment followed by water quenching from the solution temperature, a significant amount of Ag_2Al phase was observed and it was difficult to suppress the precipitation of Ag_2Al phase during the quenching due to the quite high precipitation rate. The solubility was negligible small after the precipitation treatmnnt. By the chemical dealloying, fine skeletal Ag was formed from Ag in the α phase and no Ag_2Al phase was decomposed and contributed to the formation of the skeletal Ag. The rapid solidification was *e effective to high productivity for the skeletal Ag and about 80% of the addition of Ag was recovered as the skeletal Ag. On the other hand, in both other precursors. the rate of the recovery was quite low and less than 10%. The rapid solidification root for the precursor preparation was quite excellent. The specific surface area was about 25m_2/g. The obtained skeletal Ag showed high activity for decompostion of 2H_2O_2→2H_2O+O_2. High performance in another reactions will be expected. Less