Amino-functionalized graphene oxide was reacted with isocyanate monomer to evaluate the potential application of GO-NH₂ as a functional filler for the preparation of polyurethane nanocomposites. A set of advanced techniques (XRD, FTIR spectroscopy, Raman spectroscopy, and TEM) was used to characterize the functionalized samples, together with elemental analysis and XPS, which provided valuable information on the total N content and the nitrogen (chemical) speciation, respectively. In addition, a simple and fast spectrophotometric method was developed for the estimation of accessible amino groups (functional speciation). The method is based on the interaction of NH₂ groups with the anionic dye acid orange 7 under appropriate conditions (pH = 3.6) and shows good precision. It can be advantageously used for the fast evaluation of the GO-NH₂ reactivity with isocyanate monomer and its applicability as the polymer filler.

The graphene oxide (GO) interaction with methylene blue (MB) cationic dye was studied in an aqueous solution at different pH during MB adsorption. The mutual interaction of MB with GO surface was studied and evaluated by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The π-π and electrostatic interaction of MB with GO surface are the main types of interactions, and the XRD data show the monomeric arrangement of MB cation with GO. The GO surface functional groups and point of zero charge (PZC) were determined by acid-base titration. Suitability of zeta-potential measurement and acid-base titration method was briefly discussed. The quality of prepared GO was evaluated by Raman spectroscopy, XRD, and atomic force microscope (AFM). The experimental adsorption equilibrium data were analyzed using Langmuir, Langmuir-Freundlich, Freundlich, and Temkin isotherms. The GO maximum adsorption capacity increases with higher pH, that is ascribed to the facile interaction of negatively charged GO with positively charged MB structure.

The unusual ability of cerium oxide to cleave phosphoester bonds under relatively mild (ambient) conditions was demonstrated using thiamine pyrophosphate (TPP) and nicotinamide adenine dinucleotide (NAD) as model compounds. This phosphatase-mimetic ability can be exploited in biology or medicine, e.g., for protein design; however, it represents a potential threat to vital systems in living organisms, such as the phosphate backbone of DNA and RNA. The ability of cerium oxide to promote the cleavage of the bridging pyrophosphate group in the NAD molecule was examined for the first time; it was shown that the cleavage products differ markedly from the commonly observed products of enzymatic or non-enzymatic hydrolysis of NAD. This ability is highly specific for cerium oxide; it was not observed to a comparable extent with any of the other tested metal oxides (La₂O₃, Nd₂O₃, Pr₆O₁₁, TiO₂, manganese oxide and several iron oxides). The phosphatase-mimetic ability stems from the unique properties of cerium cations and may be related to measurable and, to some extent, adjustable characteristics, such as crystallinity, surface area, Ce³⁺/Ce⁴⁺ ratio or the content of surface functional groups. The in-house prepared nanocrystalline cerium oxide exhibited a markedly higher phosphatase-mimetic ability than the commercial nanoceria. The interactions of the cerium oxide nanoparticles with TPP and NAD were also examined with the aid of molecular dynamics simulations.

Natural raw mineral tungstenite (WS₂) was exfoliated to single-layer sheets using high intensity ultrasound.