Recent advancement in the nanotechnology has led to a tremendous interest in 3D bicontinuous nanoporous precious metal structures due to their wide range of technological applications in nanobonding, catalysis, sensing, biotechnology, drug delivery, separation science, filtrations systems, energy storage, X-ray optics, accelerator components, etc. This study investigates the mechanism of formation of these unique nanostructures from binary/ternary metal alloys using in situ small angle X-ray scattering (SAXS). Kinetics of porosity evolution in 3D bicontinuous nanoporous precious metal structures have been studied and real time SAXS data was collected at the Advanced Photon Source using the X-ray beam line at sector 12-ID-C. The nanoporous structures are produced by the selective dissolution of the less noble component of a binary/ternary metal alloy in nitric acid.<br/>Morphological examination of the evolving structures shows the presence of relatively large sized cylindrical pores ~ 80 nm within the bicontinuous nanoporous metal framework. This finding reflects the hierarchical porosity of the evolving bicontinuous structure.<br/>The effect of nitric acid concentration on the porosity evolution kinetics and final morphology of the nanoporous framework has been studied. The SAXS and scanning electron microscopy (SEM) results indicated that density of the cylindrical nanopores is inversely proportional to the nitric acid concentration.

Open circuit chemical corrosion drives porosity evolution of 3D bicontinuous nanoporous precious metal structures: <i>In situ</i> and real time kinetic study via synchrotron small angle X-ray scattering

256th National Meeting (2018)

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Open circuit chemical corrosion drives porosity evolution of 3D bicontinuous nanoporous precious metal structures: In situ and real time kinetic study via synchrotron small angle X-ray scattering