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Micrometer wire-like PtCu catalysts with nanoporous structure and tunable composition were fabricated by dealloying Pt3Cu97. When the Pt:Cu ratio is lower than 1:99, dealloying results in dispersed PtCu nanoporous nanoparticles and/or single nanoparticles. Material characterization by X-ray diffraction and electron microscope shows that the formation of wire-like morphology is due to the large-scale shrink of the long rod-like alloy grains during the dealloying. The composition of the dealloyed nanoporous PtCu can be widely tuned by changing the concentration of the dealloying solution. Electrochemical test shows that the wire-like porous PtCu alloys show enhanced and composition-dependent catalytic activity for H2O2 electro-reduction.

By one-step dealloying a single phase Au 5 Cu 25 Mn 70 alloy, nanoporous AuCu alloys (np-AuCu) with widely tuned Au:Cu ratio are obtained. The one-step corrosion in (NH 4 ) 2 SO 4 solution involves two step dealloying process. The first one is fast dealloying of Mn, resulting in np-Au 16 Cu 84 . The second step is slow etching of Cu, which is used to tune the ratio of Cu/Au on the AuCu nano-ligament surface. Electrochemical measurements exhibit that the electrocatalytic activities of ultrafine np-AuCu towards glucose oxidation and H 2 O 2 reduction depend on the ratios of the Au:Cu. The activities follow the order that np-Au 66 Cu 34 > np-Au 58 Cu 42 > np-Au 78 Cu 22 > np-Au.

A free-standing nanoporous YNiCo metal/metal-oxide composite with hierarchical porosity is fabricated by chemically dealloying Al 85 Y 6 Ni 6 Co 3 metallic glass in alkaline solutions. The mixed core–shell-like metal/metal-oxide structure formed during dealloying due to the active properties of these metals. Time-dependent etching experiments suggest that the formation of large and small pores occur simultaneously, which may be related to the different dissolution rate of Al at different sites. The nanoporous composite with a highly conductive metal core exhibits a high areal capacitance. Moreover, this strategy can be extended to fabricate other nanoporous composites considering that the composition of metallic glass can be easily tuned.

The effect of amorphous structure on corrosion is a long-term puzzling problem. To elucidate this relationship, a Zr2Ni metallic glass and its single crystal counterpart were selected, in which they are both homogeneous in composition and structure. The corrosion behaviour has been evaluated in 0.1 M NaCl aqueous solution. Compared with the single crystal, the amorphous alloy presents a higher corrosion resistance. The passive film formed on the amorphous alloy contains more ZrO2 and less NiO content. These results reflect that the amorphous structure could effectively influence the composition and compactability of passive films.