The role of nanotechnology is increasingly important in our society. Through it, scientists are acquiring the ability to understand the structure and properties of materials and manipulate them at the scale of atoms and molecules. Nanomaterials are at the forefront of the rapidly growing field of nanotechnology. The synthesis of nanostructured materials, especially metallic nanoparticles, has attracted tremendous interest over the past decade due to their unique properties, making these materials excellent and indispensable in many areas of human activity. These special properties can be attributed to the small size and large specific surface area of nanoparticles, which are very different from those of bulk materials. Nanoparticles of different sizes and shapes are needed for many applications, so a variety of protocols are required to produce monodisperse nanoparticles with controlled morphology. The purpose of this review is firstly to introduce the reader to the basic aspects related to the field of nanotechnology and, secondly, to discuss metallic nanoparticles in greater detail. This article explains the basic concepts of nanotechnology, introduces methods for synthesizing nanoparticles, and describes their types, properties, and possible applications. Of many methods proposed for the synthesis of metal nanoparticles, a chemical reduction is usually preferred because it is easy to perform, cost-effective, efficient, and also allows control of the structural parameters through optimization of the synthesis conditions. Therefore, a chemical reduction method is discussed in more detail—each factor needed for the synthesis of nanoparticles by chemical reduction is described in detail, i.e., metal precursors, solvents, reducing agents, and stabilizers. The methods that are used to characterize nanomaterials are described. Finally, based on the available literature collection, it is shown how changing the synthesis parameters/methods affects the final characteristics of nanoparticles.

A new catalyst based on biosilica doped with palladium(II) chloride nanoparticles was prepared and tested for efficient degradation of methyl orange (MO) in water solution under UV light excitation. The obtained photocatalyst was characterized by X-ray diffraction, TEM and N₂ adsorption/desorption isotherms. The photocatalytic degradation process was studied as a function of pH of the solution, temperature, UV irradiation time, and MO initial concentration. The possibilities of recycling and durability of the prepared photocatalysts were also tested. Products of photocatalytic degradation were identified by liquid chromatography–mass spectrometry analyses. The photocatalyst exhibited excellent photodegradation activity toward MO degradation under UV light irradiation. Rapid photocatalytic degradation was found to take place within one minute with an efficiency of 85% reaching over 98% after 75 min. The proposed mechanism of photodegradation is based on the assumption that both HO^• and O₂^•− radicals, as strongly oxidizing species that can participate in the dye degradation reaction, are generated by the attacks of photons emitted from diatom biosilica (photonic scattering effect) under the influence of UV light excitation. The degradation efficiency significantly increases as the intensity of photons emitted from biosilica is enhanced by palladium(II) chloride nanoparticles immobilized on biosilica (synergetic photonic scattering effect).

Hydrodeoxygenation (HDO) carried out under mildest possible experimental conditions (temperatures and hydrogen pressures) is one of the alternative methods of upgrading pyrolytic oils from biomass, leading to high quality biofuels.

According to recent trends, people are more interested in cosmetic products based on natural raw materials, known to be safe for humans, including extracts obtained from selected plants, rich in active ingredients, such as proteins, vitamins, micro- and macro-elements, phospholipids, antioxidants, and natural preservatives. An example of such raw materials is Tremella fuciformis extract, which is a natural alternative to hyaluronic acid. It retains water deep in the skin cells and stimulates the skin to fight free radicals, which are responsible for the premature aging of the skin. The aim of this study was to optimize the composition of cosmetic formulations based on natural substitutes for the synthetic substances, as well as their characterization, which included the determination of the physicochemical and skin care properties. Formulations containing Tremella fuciformis extract had the effect of reducing TEWL by 12.4%, compared to a formulation that did not contain this active ingredient, and allowed adequate hydration of the epidermis, which was confirmed by apparatus methods. Additionally, dermatological tests were also conducted for the formulations obtained, which showed that no erythema or swelling/irritation was observed in any of the test volunteers 48 and 72 h after the application of the product.