Morphology Control and Functionalization of Nanoporous Metals

采用气相沉积（GD）法和选择性蚀刻（SE）法制备了具有纳米尺寸开孔道的纳米孔（np-） Au膜。通过STM和SEM的透气性测量和表面观察表明，GD np-Au的通道直径和面积密度分别为几nm和几%，SE np-Au的通道直径和面积密度分别为10 ~ 60 nm和20%左右。单轴压缩SE - np-Au可以减小通道直径和面积密度。当BET表面积为6.4 m^2/g时，SE np-Au膜的电阻率R高达大块Au膜的25倍左右，而当BET表面积为32 m^2/g时，其电阻率R约为大块Au膜的400倍。此外，当膜周围的大气从真空开始暴露于空气中时，电阻率突然下降了约0.1%。相反，从真空到空气的大气变化导致电阻率突然增加0.1%。当东南铌金暴露在干燥空气中时，这种电阻率变化大大减小。这些观察结果表明，水分子的解吸和吸收分别随着电阻率的增大和减小而变化。

Nanoporous (np-) Au membranes with nm sized open channels were prepared by both the gas-deposition (GD) method and selective etching (SE) of Ag from a Au-Ag alloy. The gas permeability measurement and surface observations by using STM and SEM indicated that, the diameter and area density of the channel in GD np-Au were a few nm and about a few% and those of SE np-Au about 10〜60 nm and about 20%, respectively. The diameter and area density of the channels could be reduced by uniaxial compression of SE np-Au. The resistivity R of the SE np-Au membrane with the BET surface area of 6.4 m^2/g was as high as about 25 times higher than that of the bulk Au and that with 32 m^2/g about 400 times higher. Further, the resistivity showed an abrupt decrease by about 0.1% when the atmosphere around the membrane was started to expose to the air from vacuum. In contrast, the atmospheric change from vacuum to the air caused an abrupt increase of the resistivity by 0.1%. This resistivity change was much reduced when the SE np-Au was exposed to the dried air. These observations suggest that desorption and absorption of water molecules was detected as the increase and decrease in the resistivity, respectively.