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Characterized by a large surface area to volume ratio, nanostructured metal oxides possess unique chemical and physical properties with applications in electronics, catalysis, sensors, etc. In this study, Mo3Al8, an intermetallic compound, has been used as a precursor to obtain nanostructured molybdenum oxides. It was prepared into ribbons by arc-melting and melt-spinning techniques. Single and double-step free corrosion of the as-quenched material have been studied in 1 M KOH, 1 M HF and 1.25 M FeCl3 at room temperature. In both cases, nanostructured molybdenum oxides were obtained on a surface layer a few microns thick. Two of the as-prepared samples were tested for their electrocatalytic capability for hydrogen evolution reaction (HER) in 0.5 M H2SO4 giving low onset potential (−50 mV, −45 mV), small Tafel slopes (92 mV dec−1, 9 mV dec−1) and high exchange current densities (0.08 mA cm−2, 0.35 mA cm−2 respectively). The proposed nanostructured molybdenum oxides are cost-effective and sustainable due to the cheap and abundant starting material used and the simple synthetic route, paving the way for their possible application as HER electrocatalysts.

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Fe and Pd thin film samples have been fabricated in a rapid fashion utilizing the versatile technique of dynamic hydrogen bubble template (DHBT) method via potentiostatic electrodeposition over a copper substrate. The morphology of the samples is dendritic, with the composition being directly proportional to the deposition time. All the samples have been tested as SERS substrates for the detection of Rhodamine 6G (R6G) dye. The samples perform very well, with the best performance shown by the Pd samples. The lowest detectable R6G concentration was found to be 10−6 M (479 μgL−1) by one of the Pd samples with the deposition time of 180 s. The highest enhancement of signals noticed in this sample can be attributed to its morphology, which is more nanostructured compared to other samples, which is extremely conducive to the phenomenon of localized surface plasmon resonance (LSPR). Overall, these samples are cheaper, easy to prepare with a rapid fabrication method, and show appreciable SERS performance.

Dense and mesoporous FePd nanowires (NWs) with 45 to 60 at.% Pd content were successfully fabricated by template- and micelle-assisted pulsed potentiostatic electrodeposition using nanoporous anodic alumina and polycarbonate templates of varying pore sizes. An FePd electrolyte was utilized for obtaining dense NWs while a block copolymer, P-123, was added to this electrolyte as the micelle-forming surfactant to produce mesoporous NWs. The structural and magnetic properties of the NWs were investigated by electron microscopy, X-ray diffraction, and vibrating sample magnetometry. The as-prepared NWs were single phase with a face-centered cubic structure exhibiting 3.1 µm to 7.1 µm of length. Mesoporous NWs revealed a core-shell structure where the porosity was only witnessed in the internal volume of the NW while the outer surface remained non-porous. Magnetic measurements revealed that the samples displayed a soft ferromagnetic behavior that depended on the shape anisotropy and the interwire dipolar interactions. The mesoporous core and dense shell structure of the NWs were seen to be slightly affecting the magnetic properties. Moreover, mesoporous NWs performed excellently as SERS substrates for the detection of 4,4′-bipyridine, showing a low detection limit of 10−12 M. The signal enhancement can be attributed to the mesoporous morphology as well as the close proximity of the embedded NWs being conducive to localized surface plasmon resonance.

In this study, we report nanoporous gold (NPG) as an economic, efficient, and stable alternative electrocatalyst for methanol electro-oxidation. The said sample was successfully prepared from an Fe-rich metastable Au33Fe67 supersaturated solid solution acting as the precursor, which was formed into ribbons by the phenomenon of rapid solidification using melt-spinning technique. The as‑quenched ribbon was then chemically dealloyed in 1 M HCl at 70 °C for different durations of time. A homogeneous, free-standing, and mechanically stable NPG sample was obtained with tunable ligament shape and size. The morphology and composition were characterized by using SEM with EDS, while the structure by XRD. The sample was examined as an electrocatalyst for methanol electro-oxidation profiting off its large surface area; cyclic voltammetry (CV) was the technique employed for electrochemical studies. In a basic solution of methanol and KOH, the sample displays a low peak potential of 0.47 V vs. Ag/AgCl for methanol electro-oxidation with a high peak current density of 0.43 mA/cm2. In addition, it demonstrates outstanding stability and high poisoning tolerance. It is noteworthy that the fabrication process of the NPG sample from start to end was intentionally opted to be sustainable, cost-effective, rapid, and feasible. The usage of critical raw materials was avoided. As a whole, the properties and results put forth by the NPG sample make it an inexpensive, sustainable, and excellent alternative as an electrocatalyst for methanol electro-oxidation.