Carbon supported Pt nanoparticles with diameters ranging from 2 to 28 nm have been studied using X-ray diffraction. The unit cell parameter of synthesized Pt/C nanoparticles is always lower than that of bulk Pt. By decreasing the average particle size D to approximately 2 nm, the unit cell parameter a nonlinearly decreases by about 0.03 Å which corresponds to a variation of 0.7% in comparison to bulk Pt, and the size effect is predominant for sizes ranging from 2 to 10 nm. The dependence a(1/D) is approximated well using a straight line with a slope of −0.0555 ± 0.0067 nm⁻¹ and an intercept of −3.9230 ± 0.0017 Å. For interpreting the obtained experimental dependence of the unit cell parameter of Pt/C nanoparticles, four different theoretical approaches such as the thermal vacancy mechanism, continuous-medium model, Laplace pressure, and bond order–length–strength correlation mechanism, were used. Comparison of the calculated dependencies, based on the above models, with the experimental ones, shows that the continuous-medium model agrees best with the experimentally found unit cell parameter dependence of our carbon supported Pt nanoparticles.

Plant biomass is considered the main source of renewable carbon raw materials, which is a viable alternative to crude oil and natural gas and provides compounds with a low carbon footprint. The most promising direction for the conversion of biomass is the synthesis of 5-hydroxymethylfurfural, which is regarded as a platform chemical, the basis for the synthesis of valuable compounds, including monomers and polymers. The move of the polymer industry to renewable plant materials will contribute to solving global environmental problems and ensure the sustainability and environmental safety of plastics production. This review analyzes recent advances in the preparation of key C₆-furan platform chemicals, such as 5-hydroxymethylfurfural, 2,5-furandicarboxylic acid, 2,5-diformylfuran, 2,5-bis(hydroxymethyl)furan, levulinic acid, and their use for the production of monomers and polymers based on renewable plant biomass. Production processes of widely known furan polyesters and polyamides, such as polyethylene-, polypropylene-, polybutylene furanoates, polyhexamethylene furanamide, are considered, as well as developments towards novel promising materials that are furan copolymers and polymer mixtures. For the first time, studies have been systematized aimed at converting liquid and solid wastes of the synthesis of platform chemicals, known as humins, into a range of value-added products, including organic compounds, porous carbon materials, thermosetting binders, and anticorrosive coatings that can replace similar materials based on fossil raw materials. Economic and environmental prospects and problems of production and consumption of furan polymers are considered. The bibliography includes 275 references.