Dry reforming of methane (DRM) over an Ni-based catalyst is an innovative research area due to the growing environmental awareness about mitigating global warming gases (CH₄ and CO₂) and creating a greener route of synthesis. Herein, 5% Ni supported on ZrO₂ obtained from various sources was prepared by the impregnation method. The catalysts were calcined at 600, 700, and 800 °C. Furthermore, Ni-RC stabilized with MgO, SiO₂, TiO₂, and Y₂O₃ were tested. Characterization techniques employed comprise the N₂ physisorption, infrared spectroscopy, Raman, thermogravimetric analysis, XRD, and TEM. The results of the present study indicated that the ZrO₂ support source had a profound effect on the overall performance of the process. The best catalyst Ni-RC gave an average conversion of CH₄ and CO₂ of 61.5% and 63.6% and the least deactivation of 10.3%. The calcination pretreatment differently influenced the catalyst performance. When the average methane conversion was higher than 40%, increasing the calcination temperature decreased the activity. While for the low activity catalysts with an average methane conversion of less than 40% the impact of the calcination temperature did not constantly decrease with the temperature rise. The stabilization of Ni-RC denoted the preference Y₂O₃ stabilized catalyst with average values of CH₄ and CO₂ conversion of about 67% and 72%, respectively. The thorough study and fine correlation will be advantageous for technologically suitable Ni-15Y-RC catalysts for DRM.

Propolis (bee glue) is a complex, phyto-based resinous material obtained from beehives. Its chemical and biological properties vary with respect to bee species, type of plants, geographical location, and climate of a particular area. This study was planned with the aim of determining the chemical composition and to investigate various properties (against oxidants and microbes) of different extracts of Saudi propolis collected from Arabian honey bee (Apis mellifera jemenitica) colonies headed by young queens. Chemical analysis of propolis extracts with different solvents, i.e., ethyl acetate (Eac), methanol (Met), butanol (BuT), and hexane (Hex) was done through colorimetry for the total phenolic content (TPC) and total flavonoid content (TFC) evaluation. For separation and extensive characterization of the Met extract, chromatography and ¹H NMR were deployed. Six different microorganisms were selected to analyze the Saudi-propolis-based extract’s antimicrobial nature by measuring zones of inhibition (ZOI) and minimum inhibitory concentration (MIC). Molecular docking was done by utilizing AutodDock, and sketching of ligands was performed through Marvin Chem Sketch (MCS), and the resultant data after 2D and 3D clean were stored in .mol format. The highest TFC (96.65 mg quercetin equivalents (QE)/g of propolis) and TPC (325 mg gallic acid equivalents (GAE)/g of propolis) were noted for Met. Six familiar compounds were isolated, and recognition was done with NMR. Met extract showed the greatest 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) free radical scavenging activity and Ferric Reducing Antioxidant Power (FRAP). Met showed max microbial activity against Staphylococcus aureus (ZOI = 18.67 mm, MIC = 0.625 mg/mL), whereas the minimum was observed in Hex against E. coli (ZOI = 6.33 mm, MIC = 2.50 mg/mL). Furthermore, the molecular docking process established the biological activity of separated compounds against HCK (Hematopoietic cell kinase) and Gyrase B of S. aureus. Moreover, the stability of protein–ligand complexes was further established through molecular dynamic simulation studies, which showed that the receptor–ligand complexes were quite stable. Results of this research will pave the way for further consolidated analysis of propolis obtained from Arabian honey bees (A. m. jemenitica).

An environmentally-benign way of producing hydrogen is methane decomposition. This study focused on methane decomposition using Fe and Fe-Ni catalysts, which were dispersed over different supports by the wet-impregnation method. We observed the effect of modifying ZrO₂ with La₂O₃ and WO₃ in terms of H₂ yield and carbon deposits. The modification led to a higher H₂ yield in all cases and WO₃-modified support gave the highest yield of about 90% and was stable throughout the reaction period. The reaction conditions were at 1 atm, 800 °C, and 4000 mL(hg_cat)⁻¹ space velocity. Adding Ni to Fe/x-ZrO₂ gave a higher H₂ yield and stability for ZrO₂ and La₂O₃ + ZrO₂-supported catalysts whose prior performances and stabilities were very poor. Catalyst samples were analyzed by characterization techniques like X-ray diffraction (XRD), nitrogen physisorption, temperature-programmed reduction (TPR), thermo-gravimetric analysis (TGA), and Raman spectroscopy. The phases of iron and the supports were identified using XRD while the BET revealed a significant decrease in the specific surface areas of fresh catalysts relative to supports. A progressive change in Fe’s oxidation state from Fe³⁺ to Fe⁰ was observed from the H₂-TPR results. The carbon deposits on Fe/ZrO₂ and Fe/La₂O₃ + ZrO₂ are mainly amorphous, while Fe/WO₃ + ZrO₂ and Fe-Ni/x-ZrO₂ are characterized by graphitic carbon.

A series of large-pore mesoporous silica (LPMS)-supported CrO_x catalysts were synthesized by hydrothermal and impregnation methods and tested for ethane dehydrogenation in the presence of CO₂ as an oxidant. To assess the effect of hydrothermal temperature treatment on the characteristics of LPMS support, different hydrothermal temperatures (100–160 °C) were studied and optimized. The optimum support was then loaded with different amounts of chromium (0, 2, 4, 8, and 11 wt % Cr). The obtained catalysts were characterized by different techniques such as XRD, BET, TEM, SEM, XPS, FTIR, and diffuse reflectance UV-Vis spectroscopy. The characterization results indicated that the sample hydrothermally treated at 130 °C exhibited the highest pore volume, a narrow pore size distribution, and a moderate BET surface area. Chromium species with various oxidation states including Cr³⁺, Cr⁶⁺, and α-Cr₂O₃ were detected in all synthesized Cr(y)/LPMS-130 catalysts. A lower Cr content resulted in the formation of Cr⁶⁺, whereas a higher Cr content dominated the α-Cr₂O₃ on the surface of the catalyst. Among the synthesized catalysts, the Cr(4)/LPMS-130 catalyst showed the highest Cr⁶⁺/Cr³⁺ ratio, indicating a good dispersion of chromium species along with a fine particle size. The ethane conversion and ethylene selectivity were 50.5 and 91.1% for Cr(4)/LPMS-130, respectively. Carbon dioxide was believed to supply enough lattice oxygen to maintain the Cr species at a higher oxidation state and to consume the hydrogen resulting from ethane cracking by a reverse water gas shift reaction.

The stability and catalytic activity of mesoporous Ni/MCM-41 promoted with a Ga loading of (0.0, 1.0, 1.5, 2.0, 2.5, and 3.0 wt %) as an innovative catalyst was examined for syngas production via CO₂ reforming of CH₄. The objective of present work was to develop a potential catalyst for CO₂ reforming of methane. For this purpose different loadings of gallium were used to promote 5% nickel catalyst supported on MCM-41. An incipient wetness impregnation method was used for preparing the catalysts and investigated at 800 °C. Physicochemical characterization techniques—including BET, XRD, TPD, TPR, TEM, and TGA—were used to characterize the catalysts. The addition of small amounts of Ga resulted in higher surface areas with a maximum surface area of 1036 m²/g for 2.5% Ga. The incorporation of Ga to the catalyst decreased the medium and strong basic sites and reduced the amount of carbon deposited. There was no weight loss for 3%Ga+5%Ni/MCM-41. The 2% Ga loading showed the highest CH₄ conversion of 88.2% and optimum stability, with an activity loss of only 1.58%. The Ga promoter raised the H₂/CO ratio from 0.9 to unity.

Nickel catalysts supported on zirconium oxide and modified by various amounts of lanthanum with 10, 15, and 20 wt.% were synthesized for CO₂ reforming of methane. The effect of La₂O₃ as a promoter on the stability of the catalyst, the amount of carbon formed, and the ratio of H₂ to CO were investigated. In this study, we observed that promoting the catalyst with La₂O₃ enhanced catalyst activities. The conversions of the feed, i.e., methane and carbon dioxide, were in the order 10La₂O₃ > 15La₂O₃ > 20La₂O₃ > 0La₂O₃, with the highest conversions being about 60% and 70% for both CH₄ and CO₂ respectively. Brunauer–Emmett–Teller (BET) analysis showed that the surface area of the catalysts decreased slightly with increasing La₂O₃ doping. We observed that 10% La₂O₃ doping had the highest specific surface area (21.6 m²/g) and the least for the un-promoted sample. The higher surface areas of the promoted samples relative to the reference catalyst is an indication of the concentration of the metals at the mouths of the pores of the support. XRD analysis identified the different phases available, which ranged from NiO species to the monoclinic and tetragonal phases of ZrO₂. Temperature programmed reduction (TPR) analysis showed that the addition of La₂O₃ lowered the activation temperature needed for the promoted catalysts. The structural changes in the morphology of the fresh catalyst were revealed by microscopic analysis. The elemental compositions of the catalyst, synthesized through energy dispersive X-ray analysis, were virtually the same as the calculated amount used for the synthesis. The thermogravimetric analysis (TGA) of spent catalysts showed that the La₂O₃ loading of 10 wt.% contributed to the gasification of carbon deposits and hence gave about 1% weight-loss after a reaction time of 7.5 h at 700 °C.