No abstract

Samarium oxide (Sm2O3) is a versatile surface for CO2 and H2 interaction and conversion. Samarium oxide-supported Ni, samarium oxide-supported Co-Ni, and samarium oxide-supported Ru-Ni catalysts were tested for CO2 methanation and were characterized by X-ray diffraction, nitrogen physisorption, infrared spectroscopy, H2-temperature programmed reduction, and X-ray photoelectron spectroscopy. Limited H2 dissociation and widely available surface carbonate and formate species over 20 wt.% Ni, dispersed over Sm2O3, resulted in ~98% CH4 selectivity. The low selectivity for CO could be due to the reforming reaction between CH4 (methanation product) and CO2. Co-impregnation of cobalt with nickel over Sm2O3 had high surface adsorbed oxygen and higher CO selectivity. On the other hand, co-impregnation of ruthenium and nickel over Sm2O3 led to more than one catalytic active site, carbonate species, lack of formate species, and 94% CH4 selectivity. It indicated the following route of CH4 synthesis over Ru-Ni/Sm2O3; carbonate → unstable formate → CO → CH4.

No abstract

The synthesis of polar functionalized polyolefin (PFP) offers improvement in mixing properties, polymer surface, and rheological properties with the potential of upgraded polyolefins for modern and ingenious applications. The synthesis of PFP from metal-based catalyzed olefin (non-polar in nature) copolymerization with polar comonomers embodies energy-efficient, atomefficient, and apparently an upfront methodology. Despite their outstanding success during conventional polymerization of olefin, 3 rd and 4 th group (early transition metal)-based catalysts, owing to their electrophilic nature, face challenges mainly due to Lewis basic sites of the polar monomers. On the contrary, late transition metal-based catalysts have also made progress, in recent years, for PFP synthesis. The recent past has also witnessed several advancements in the development of dominating palladium-based catalysts while their lower resistance towards ligand functional groups has limited the practical application of abundant and cheaper nickel-based catalysts. However, the relentless efforts of the scientific community, during the past half-decade, have indicated rigorous progress in the development of nickel-based catalysts for PFP synthesis. In this review, we have abridged the recent research trends in both early as well as late transition metal-based catalyst development. Furthermore, we have highlighted the role of transition metalbased catalysts in influencing the polymer properties.

No abstract

Polyolefin copolymers have been an important commercial product since their invention. Hence, it is crucial to study their co‐ and terpolymers due to their extensive use. In this paper, in situ synthesis of ethylene‐propylene (EP) copolymer, its terpolymer with styrene, and composites with nickel‐chromium (NiCr) layered double hydroxide (LDH) has been reported along with their thermal properties. Styrene had a significant impact on the activity, increasing the yield by 195% and 235% with an addition of 0.5 and 1.0 mL styrene, respectively, compared to neat EP. The crystallinity, melting temperature, and thermal stability decreased due to styrene; nevertheless, it performed better compared to a similar work of terpolymer where α‐olefin was the third monomer. The incorporation of NiCr LDH as a drop‐in filler during in situ polymerization affected adversely the thermal stability of the terpolymer. However, the ultrasonication treatment improved the thermal stability of the final product.

No abstract

No abstract