Photocatalytic degradation is a promising method for removing persistent organic pollutants from water because of its low cost (see solar-driven photocatalysis), high mineralisation of pollutants, and low environmental impact. Photocatalysts based on transition metal dichalcogenides (TMDs) have recently attracting high scientific interest due to their unique electrical, mechanical, and optical properties. A MoS₂ photocatalyst of the layered structure was managed to photodegrade methylene blue (MB) under visible light irradiation. The catalyst was thoroughly characterised using SEM, AFM, powder XRD, UV–Vis, Raman, and XPS measurements. The photocatalytic degradation of the MB solution was conducted under the following conditions: (i) reductive and (ii) oxidative. The impact of optical and electronic properties, and the MoS₂-MB interaction on photocatalytic activity, was discussed. The apparent rate constants (k_app) of degradation were 3.7 × 10^–3; 7.7 × 10^–3; 81.7 × 10^–3 min⁻¹ for photolysis, oxidative photocatalysis, and reductive photocatalysis. Comparison of the degradation efficiency of MB in reductive and oxidative processes indicates the important role of the reaction with the surface electron. In the oxidation process, oxygen reacts with an electron to form a superoxide anion radical involved in further transformations of the dye, whereas, in the reduction process, the addition of an electron destabilises the chromophore ring and leads to its rupture.

Molybdenum disulphide (MoS ₂ ) is a layered material with interesting photocatalytic properties.

One of the consequences of climate change is the expansion of insects’ ranges. Colonization of new habitats forces insects to adapt to new conditions, such as low temperatures in winter. Cinara tujafilina is a thermophilic anholocyclic aphid species, which reproduce exclusively parthenogenetic throughout the year, including winter. On the areas where the populations of C. tujafilina had expanded, it demonstrated its adaptation for surviving colder winters. Based on analyses of changes in body chemical composition using Fourier transform infrared (FTIR) and changes in cryoprotectant content using high performance liquid chromatography (HPLC), we showed how aphid C. tujafilina adapted to overwintering as an active stage. In the FTIR spectrum of the winter type of C. tujafilina, higher peak values originating from the carbohydrates, proteins and lipids, were observed. Glucose, trehalose, mannitol, myo-inositol and glycerol were identified in the aphid body in winter as main putative cryoprotectants to increase the insects’ tolerance to cold. The complex sugar-polyol cryoprotectant system facilitates aphids’ survival in unfavorable low temperatures.

In present work, we examine the photocatalytic properties of S-doped TiO₂ (S1, S2) compared to bare TiO₂ (S0) in present work. The photocatalytic tests were performed in alkaline aqueous solutions (pH = 10) of three differently substituted phenols (phenol (I), 4,4′-isopropylidenebisphenol (II), and 4,4′-isopropylidenebis(2,6-dibromophenol) (III)). The activity of the catalysts was evaluated by monitoring I, II, III degradation in the reaction mixture. The physicochemical properties (particle size, ζ-potential, E_bg, Eu, E⁰_cb, E⁰_vb, σ_o, K_L) of the catalysts were established, and we demonstrated their influence on degradation reaction kinetics. Substrate degradation rates are consistent with first-order kinetics. The apparent conversion constants of the tested compounds (k_app) in all cases reveal the sulfur-loaded catalyst S2 to show the best photocatalytic activity (for compound I and II S1 and S2 are similarly effective). The different efficiency of photocatalytic degradation I, II and III can be explained by the interactions between the catalyst and the substrate solution. The presence of bromine substituents in the benzene ring additionally allows reduction reactions. The yield of bromide ion release in the degradation reaction III corresponds to the Langmuir constant. The mixed oxidation-reduction degradation mechanism results in higher degradation efficiency. In general, the presence of sulfur atoms in the catalyst network improves the degradation efficiency, but too much sulfur is not desired for the reduction pathway.

Laser texturing seems to be a promising technique for reducing bacterial adhesion on titanium implant surfaces. This work aims to demonstrate the possibility of obtaining a functionally orientated surface of titanium implant elements with a specific architecture with specific bacteriological and photocatalytic properties. Femtosecond laser-generated surface structures, such as laser-induced periodic surface structures (LIPSS, wrinkles), grooves, and spikes on titanium, have been characterised by XRD, Raman spectroscopy, and scanning electron microscopy (SEM). The photocatalytic activity of the titanium surfaces produced was tested based on the degradation effect of methylene blue (MB). The correlation between the photocatalytic activity of TiO₂ coatings and their morphology and structure has been analysed. Features related to the size, shape, and distribution of the roughness patterns were found to influence the adhesion of the bacterial strain on different surfaces. On the laser-structurised surface, the adhesion of Escherichia coli bacteria were reduced by 80% compared to an untreated reference surface.