The formation of porous silicon by Pd nanoparticles-assisted chemical etching of single-crystal Si with resistivity ρ = 0.01 Ω·cm at 25 • C, 50 • C and 75 • C in HF/H 2 O 2 /H 2 O solution was studied. Porous layers of silicon were studied by optical and scanning electron microscopy, and gravimetric analysis. It is shown that por-Si, formed by Pd nanoparticles-assisted chemical etching, has the property of ethanol electrooxidation. The chromatographic analysis of ethanol electrooxidation products on por-Si/Pd shows that the main products are CO 2 , CH 4 , H 2 , CO, O 2 , acetaldehyde (CHO) + , methanol and water vapor. The mass activity of the por-Si/Pd system was investigated by measuring the short-circuit current in ethanol solutions. The influence of the thickness of porous silicon and wafer on the mass activity and the charge measured during ethanol electrooxidation was established. Additionally, the mechanism of charge transport during ethanol electrooxidation was established.

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In this paper, we are reporting on the fabrication of a porous silicon/Au and silicon filament/Au using the two-step Au-assisted chemical etching of p-type Si with a specific resistivity of 0.01, 1, and 12 Ω·cm when varying the Au deposition times. The structure analysis results show that with an increasing Au deposition time of up to 7 min, the thickness of the porous Si layer increases for the same etching duration (60 min), and the morphology of the layer changes from porous to filamentary. This paper shows that the uniform macro-porous layers with a thickness of 125.5–171.2 μm and a specific surface area of the mesopore sidewalls of 142.5–182 m2·g−1 are formed on the Si with a specific resistivity of 0.01 Ω·cm. The gradient macro-porous layers with a thickness of 220–260 μm and 210–290 μm, the specific surface area of the mesopore sidewalls of 3.7–21.7 m2·g−1 and 17–29 m2·g−1 are formed on the silicon with a specific resistivity of 1 and 12 Ω·cm, respectively. The por-Si/Au has excellent low-temperature electro oxidation performance with ethanol, the activity of ethanol oxidation is mainly due to the synergistic effect of the Au nanoparticles and porous Si. The formation mechanism of the uniform and gradient macro-porous layers and ethanol electro-oxidation on the porous/filament silicon, decorated with Au nanoparticles, was established. The por-Si/Au structures with perpendicularly oriented pores, a high por-Si layer thickness, and a low mono-Si layer thickness (with a specific resistivity of 1 Ω·cm) are optimal for an effective ethanol electro-oxidation, which has been confirmed with chronoamperometry measurements.

The effect of modifying additives such as low molecular weight polylactide (PLA) and benzyl alcohol (BA) on the degree of hydrophilicity of high molecular weight PLA before and after plasma treatment with low density and specific power per area was investigated. The lowest water contact angle (WCA) after modification was about 17°. A comparative evaluation of the formed functional groups amount, the hydrophilicity and stability of the plasma modification was carried out. WCA measurements of ageing of modified samples over time up to one year was carried out. It was found that plasma treated PLA films, obtained from tetrahydrofuran solution of high-molecular weight PLA and BA, demonstrated one of the highest ageing stability at high hydrophilicity. At the same time, the increase of the oxygen-containing functional groups amount on the modified PLA surface (about 40%, estimated by XPS) is close to the critical value in point of view of ensuring both high hydrophilicity and stability of the PLA surface after the modification.