Thin cupric oxide (Cu₂O) nanobelts with width of few tens of nanometers to few hundreds of nanometers were fabricated in anhydrous ethanol on nanoporous copper templates that was prepared via dealloying amorphous Ti₄₀Cu₆₀ ribbons in hydrofluoric acid solutions at 348 K. The Cu₂O octahedral particles preferentially form in the water, and nanobelts readily undergo the growth along the lengthwise and widthwise in the anhydrous ethanol. The ethanol molecules serve as stabilizing or capping reagents, and play a key role of the formation of two-dimensional Cu₂O nanobelts. Cu atoms at weak sites (i.e., twin boundary) on the nanoporous Cu ligaments are ionized to form Cu²⁺ cations, and then react with OH⁻ to form Cu₂O and H₂O. The two-dimensional growth of Cu₂O nanostructure is preferred in anhydrous ethanol due to the suppression of random growth of Cu₂O nanoarchitectures by ethanol. Cu₂O nanobelts have superior photodegradation performance of methyl orange, three times higher than nanoporous Cu.

Nanoporous structures were fabricated from Fe₇₆Si₉B₁₀P₅ amorphous alloy annealed at 773 K by dealloying in 0.05 M H₂SO₄ solution, as a result of preferential dissolution of α-Fe grains in form of the micro-coupling cells between α-Fe and cathodic residual phases. Nanoporous Fe-Si-B-P powders exhibit much better degradation performance to methyl orange and direct blue azo dyes compared with gas-atomized Fe₇₆Si₉B₁₀P₅ amorphous powders and commercial Fe powders. The degradation reaction rate constants of nanoporous powders are almost one order higher than those of the amorphous counterpart powders and Fe powders, accompanying with lower activation energies of 19.5 and 26.8 kJ mol⁻¹ for the degradation reactions of methyl orange and direct blue azo dyes, respectively. The large surface area of the nanoporous structure, and the existence of metalloids as well as residual amorphous phase with high catalytic activity are responsible for the enhanced azo-dyes degradation performance of the nanoporous Fe-Si-B-P powders.

Two types of cupric oxide (Cu₂O) nanoarchitectures (nanobelts and nanopetal networks) have been achieved via immersion nanoporous copper (NPC) templates in anhydrous ethanol. NPC templates with different defect densities have been prepared by dealloying amorphous Ti₆₀Cu₄₀ ribbons in a mixture solution of hydrofluoric acid and polyvinylpyrrolidone (PVP) with different ratios of HF/PVP. Both a water molecule reactant acting as OH⁻ reservoir and the ethanol molecule serving as stabilizing or capping reagent for inhibiting the random growth of Cu₂Oplayed a role of the formation of 2-dimensional Cu₂O nanoarchitectures. Cu₂O nanobelts are preferred to form in anhydrous ethanol on the NPC templates from Ti₆₀Cu₄₀ ribbons dealloying in the solution with low HF concentration and small addition of PVP; and Cu₂O nanopetals are tended to grow in anhydrous ethanol from the NPC templates from Ti₆₀Cu₄₀ ribbons dealloying in the solution with high HF concentration and large addition of PVP. With increasing the immersion time in anhydrous ethanol, Cu₂O nanopetals united together to create porous networks about 300 nm in thickness. The defect sites (i.e., twin boundary) on nanoporous Cu ligaments preferentially served as nucleation sites for Cu₂O nanocrystals, and the higher defect density leads to the formation of uniform Cu₂O layer. Synergistic effect of initial microstructure of NPC templates and stabilizing agent of ethanol molecule results in different Cu₂O nanoarchitectures.

In the present study, a food additive, tert-butylhydroquinone (TBHQ), was selectively and sensitively determined by both colorimetric and spectrofluorimetric methods using bovine serum albumin capped gold nanoclusters (BSA-AuNCs) for the first time. The AuNCs were synthesized by a one-pot method using BSA as a stabilizing agent in an alkaline medium at room temperature. The synthesized BSA-AuNCs were then confirmed by UV-vis spectroscopy, fluorimetry and HR-TEM. The absence of a surface plasmon resonance band and appearance of red luminescence in a UV chamber confirmed the formation of AuNCs. The HR-TEM images exhibited the average size of BSA-AuNCs as 1.8 nm. The BSA-AuNCs showed an emission maximum at 663 nm and were utilized for the colorimetric and fluorimetric detection of TBHQ. The addition of 50 μM TBHQ to the BSA-AuNCs leads to the disappearance of the red luminescence as well as the quenching of the emission at 663 nm. This is due to the strong electrostatic interaction between TBHQ and BSA-AuNCs and it was confirmed from the decrease in the zeta potential value from −43.7 to −0.9 mV. The emission intensity of the BSA-AuNCs does not change when adding higher concentrations of major interferents including propyl gallate, butyl hydroxyltoluene, butyl hydroxyanisole and metal ions. On the other hand, the emission intensity decreases when increasing the concentration of TBHQ from 2.5 to 50 μM and the limit of detection was found to be 72 nM (S/N = 3). The practical application of the BSA-AuNCs was determined in oil samples for determining TBHQ and the results were validated with the GC-MS method.