Nanoporous Gold Ribbons with Bimodal Channel Size Distributions by Chemical Dealloying of Al-Au Alloys

We present a novel and simple strategy to synthesize nanoporous gold (NPG) ribbons with bimodal channel size distributions. The NPG ribbons can be fabricated from Al-Au alloys through rapid solidification and chemical dealloying. The microstructure of these NPG ribbons was characterized using X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, transmission electron microscopy, and high-resolution transmission electron microscopy. These NPG ribbons are composed of large-sized channels (hundreds of nanometers) with highly porous channel walls (tens of nanometers). Both large- and small-sized channels are 3D, open, and bicontinuous. The length scales of the large-sized channels can be modulated by changing the alloy composition, and those of small ligaments/channels in the channel walls can be tuned by changing the dealloying solution.