Nanoporous noble metals by alloy corrosion : formation process, microstructure and surface-stress-charge behaviors

摘要

This work attempts to explore following aspects of nanoporous noble metal and alloys structures prepared by dealloying: a) inter-relation between formation process, microstructure and property, b) study of the effect of dealloying rate, structure size and defect generation in the microstructure on the volume shrinkage during dealloying, c) determination of the physical properties of the three dimensional bi-continuous nanoporous morphology, d) stabilization of porous microstructure by Pt addition, e) the correlation between amplitude of the surface-stress-induced strain and size of the length scale in nanoporous structures prepared by dealloying, f) study of the effect of adsorbate coverage on the surface-stress-charge response of the metal surface at nanoporous metal-electrolyte interface. For the first time, volume shrinkage during dealloying was reported in Au-Ag alloys, which is not consistent with the present model of dealloying based on surface diffusion. For the first time, Z-contrast tomography was carried out on nanoporous metals prepared by dealloying to visualize it inherent in three dimension morphology.