Graphitic carbon nitride (gCN­(H)) is a semiconductor with high mechanical and thermal stability which provides good dispersion of metal particles. As it is resistant to corrosion, it constitutes an alternative to carbon black as a catalyst support in polymer electrolyte membrane fuel cells (PEMFCs), e.g., in alcohol oxidation reactions. In this research work, gCN (H)-supported catalyst has been characterized by spectroscopic (UV–vis, IR, Raman) and microscopy techniques (SEM, TEM, AFM) in order to gain deeper understanding of the relationship between material properties and electrochemical activity. Ni-doped graphitic carbon nitride (Ni/gCN­(H)) was tested in electrooxidation of ethanol demonstrating comparatively high peak current density and interesting photocatalytic properties. The obtained results suggest that the improvement of the activity and selectivity of Ni-modified gCN­(H) can be related to the chemical and electronic material modification, while the sample morphology and topology is preserved. Metal–support interactions account for the high photocatalytic activity, superior to that of the Pt counterpart.

Within the Waste2Fuel project, innovative, high-performance, and cost-effective fuel production methods are developed to target the “closed carbon cycle”. The catalysts supported on different metal oxides were characterized by XRD, XPS, Raman, UV-Vis, temperature-programmed techniques; then, they were tested in CO2 hydrogenation at 1 bar. Moreover, the V2O5 promotion was studied for Ni/Al2O3 catalyst. The precisely designed hydrotalcite-derived catalyst and vanadia-promoted Ni-catalysts deliver exceptional conversions for the studied processes, presenting high durability and selectivity, outperforming the best-known catalysts. The equilibrium conversion was reached at temperatures around 623 K, with the primary product of reaction CH4 (>97% CH4 yield). Although the Ni loading in hydrotalcite-derived NiWP is lower by more than 40%, compared to reference NiR catalyst and available commercial samples, the activity increases for this sample, reaching almost equilibrium values (GHSV = 1.2 × 104 h–1, 1 atm, and 293 K).

CO2 methanation is a very promising technology for the production of alternative fuels with the simultaneous use of greenhouse gases. Therefore, intensive research is carried out on the optimization of catalysts with excellent properties for operation in the area of low temperatures. Here, we present research on a catalyst composed of 19 wt % NiO supported on alumina/calcium aluminate. The catalyst was modified with V2O5 in order to be suited for extrusion and scale-up in the frame of power to gas technology. Samples with various vanadium contents (Ni–xV, where x represents the amount of vanadium) were prepared in the form of ground granules obtained from 0.5 mm diameter spherical grains. X-ray diffraction (XRD), transmission electron microscopy (TEM), skeletal infrared (IR), diffuse reflectance ultraviolet–visible-near-infrared (DR-UV–vis-NIR), and X-ray photoelectron (XPS) spectroscopies, as well as H2 temperature-programmed reduction (H2-TPR), were used to characterize the samples. Catalytic performances of the catalyst samples were tested in CO2 hydrogenation at 1 atm. Among the many supported Ni catalysts tested in our laboratories, the catalysts of 0.5 and 1 wt % V showed very high activity, with the highest CH4 yield of 97% at 623 K. These catalysts exhibited 100% CH4 selectivity up to 673 K. The excellent performances of the studied catalysts are attributed to the possible formation of Ni–V solid solution alloy nanoparticles.

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The cross-linking temperature of polymers may affect the surface characteristics and molecular arrangement, which are responsible for their mechanical and physico-chemical properties. The aim of this research was to determine and explain in detail the mechanism of unit interlinkage of two-component chitosan/1,3-β-d-glucan matrices gelled at 90 °C. This required identifying functional groups interacting with each other and assessing surface topography providing material chemical composition. For this purpose, various spectroscopic and microscopic approaches, such as attenuated total reflection Fourier transform infrared spectroscopy (ATR FT-IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM), were applied. The results indicate the involvement mainly of the C-C and C-H groups and C=O⋯HN moieties in the process of biomaterial polymerization. Strong chemical interactions and ionocovalent bonds between the N-glucosamine moieties of chitosan and 1,3-β-d-glucan units were demonstrated, which was also reflected in the uniform surface of the sample without segregation. These unique properties, hybrid character and proper cell response may imply the potential application of studied biomaterial as biocompatible scaffolds used in regenerative medicine, especially in bone restoration and/or wound healing.

Within the Waste2Fuel project, innovative, high-performance, and cost-effective fuel production methods from municipal solid wastes (MSWs) are sought for application as energy carriers or direct drop-in fuels/chemicals in the near-future low-carbon power generation systems and internal combustion engines. Among the studied energy vectors, C1-C2 alcohols and ethers are mainly addressed. This study presents a potential bio-derived ethanol oxidative coupling in the gas phase in multicomponent systems derived from hydrotalcite-containing precursors. The reaction of alcohol coupling to ethers has great importance due to their uses in different fields. The samples have been synthesized by the co-precipitation method via layered double hydroxide (LDH) material synthesis, with a controlled pH, where the M(II)/M(III) ≈ 0.35. The chemical composition and topology of the sample surface play essential roles in catalyst activity and product distribution. The multiple redox couples Ni2+/Ni3+, Cr2+/Cr3+, Mn2+/Mn3+, and the oxygen-vacant sites were considered as the main active sites. The introduction of Cr (Cr3+/Cr4+) and Mn (Mn3+/Mn4+) into the crystal lattice could enhance the number of oxygen vacancies and affect the acid/base properties of derived mixed oxides, which are considered as crucial parameters for process selectivity towards bio-DEE and bio-butanol, preventing long CH chain formation and coke deposition at the same time.

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