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In this paper we describe a biopolymer-assisted hydrothermal approach to the synthesis of gold sponges. This is carried out by transferring a hyaluronic acid potassium salt/HAuCl 4 aqueous solution into a stainless steel autoclave with a Teflon liner and heating in an oven at 180 • C for 6 h. Here, hyaluronic acid potassium salt plays three roles in the synthesis, namely, stabilization, reduction, and as a soft template. Field emission scanning electron microscopy images, energy-dispersive x-ray spectroscopy, and x-ray diffraction reveal that the materials obtained consist of an interconnected framework of face-centred cubic metallic gold filaments, which is approximately 0.6 µm in width and composed of fused micrometre-sized particles that enclose pores 1-4 µm in size. The test of surface-enhanced Raman scattering (SERS) from 4-mercaptobenzoic acid shows that the prepared gold sponges are an active SERS substrate. This is largely because they had an increased number of particle junctions, which are SERS active sites. This route can also be extended to the fabrication of silver sponges, which are composed of fused crystallites with diameters of 200-400 nm that enclosed pores 0.4-2 µm in size. The test of SERS from Rhodamine 6G also reveals that the prepared silver sponges are likewise an excellent SERS substrate.

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Hollow Cu nano/microstructures are prepared by reduction of CuSO4 · 5 H2O with glucose by using a mild hydrothermal process. The X‐ray powder diffraction and energy‐dispersive X‐ray analysis indicate that the products are pure Cu and of cubic phase. The morphology of the products can be controlled between nanotubes and microspheres assembled from hollow nanoparticles by adjusting the concentration of sodium dodecyl sulfate. A series of experiments confirm that the concentration of the glucose and NaOH also play important roles in the formation of the hollow Cu nano/microstructures.

Unusual hierarchical stacked superstructures of cubic beta-In2S3 were fabricated via a facile hydrothermal process in the presence of a surfactant cetyltrimethylammonium bromide CTAB; the 3D superstructures were developed by helical propagation of surface steps from microflakes of 10-20 nm thickness.

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