This paper evaluated the effect of calcination temperature and the use of Mg/Al₂O₃ on the decomposition of HFC-134a. Two commercialized catalysts, Al₂O₃ and Mg/Al₂O₃, were calcined at two different temperatures (500 and 650 °C) and their physicochemical characteristics were examined by X-ray diffraction, Brunauer–Emmett–Teller analysis, and the temperature-programed desorption of ammonia and carbon dioxide analysis. The results show that, in comparison to Al₂O₃, 5% Mg/Al₂O₃ exhibited a larger Brunauer–Emmett–Teller surface area and higher acidity. The relative amount of strong acid sites of the catalysts decreased with increasing calcination temperature. Although a more than 90% decomposition rate of HFC-134a was achieved over all catalysts during the sequential decomposition test of HFC-134a using a vertical plug flow reactor connected directly to a gas chromatography/mass spectrometry system, the lifetime of the catalyst differed according to the catalyst type. Compared to Al₂O₃, Mg/Al₂O₃ revealed a longer lifetime and less coke formation due to the increased Brunauer–Emmett–Teller surface area and weak Lewis acid sites and basic sites arising from Mg impregnation. Higher temperature calcination extended the catalyst lifetime with the formation of less coke due to the smaller number of strong acid sites, which can lead to severe coke formation. A valuable by-product, trifluoroethylene, was formed as a result of the decomposition. Based on the experimental results, a reaction is proposed which reasonably explains the decomposition reaction.

Superhydrophobic coatings have attracted substantial attention owing to their potential application in various industries. Conventional textiles used in daily life are prone to staining with water and household liquids, necessitating the development of water-repellent and stain-resistant coatings. In this study, we fabricated a highly water-repellent superhydrophobic PET fabric by using an eco-friendly water-based coating process. Fluorine-free octadecyltrichlorosilane (OTS) solutions with various wt.% of hollow silica (HS) nanoparticles were used to produce a superhydrophobic surface via a facile dip coating method. Our findings revealed that the incorporation of HS nanoparticles substantially increased the water contact angle, with higher concentrations resulting in enhanced water repellency and increased surface roughness. The treated fabrics had a remarkable water contact angle of 152.4° ± 0.8°, demonstrating their superhydrophobic fiber surface. In addition, the durability of these superhydrophobic properties was investigated via a laundry procedure, which showed that the fabrics maintained their water repellency even after 20 laundering cycles. EDX and XRD analyses confirmed that the morphological evaluations did not reveal any substantial structural alterations. Significantly, the fibers maintained their strength and durability throughout the testing, enduring only minor hollow SiO₂ nanoparticle loss. This eco-friendly and cost-effective method holds great potential for application in apparel and other industries, offering an effective solution to resist water stains and improve performance in various contexts.

This paper explores the thermal and catalytic pyrolysis of HFC-134a over γ-Al₂O₃ calcined at temperatures of 550 °C (A550), 650 °C (A650), 750 °C (A750), and 850 °C (A850). The physicochemical properties of catalysts were studied through thermogravimetric analysis (TGA), Brunauer–Emmett–Teller equation for nitrogen physisorption analysis (BET), X-ray diffraction (XRD), and temperature-programmed desorption of ammonia (NH₃-TPD). The non-catalytic pyrolysis of HFC-134a showed less than 15% decomposition of HFC-134a. Catalysts increased the decomposition as A650 revealed the highest decomposition efficiency by decomposing more than 95% HFC-134a for 8 h followed by A750, A850, and A550. The larger surface area and pore volume paired with a low amount of strong acidic sites were considered as the main contributors to the comparatively longer catalytic activity of A650.

CO₂-responsive polymers have emerged as a significant class of smart materials, distinguished by their ability to reversibly alter their properties upon exposure to CO₂. Due to CO₂’s abundant availability, low cost, non-toxicity, energy efficiency, and excellent biocompatibility, these polymers offer remarkable environmental and practical advantages. This review succinctly explores recent advancements in the synthesis, mechanisms, and applications of CO₂-responsive polymers, emphasizing the pivotal roles of specific acidic and basic functional groups such as carboxylic acids, phenolic groups, amines, amidines, guanidines, and imidazoles. Advanced polymerization techniques including free radical polymerization (FRP), atom transfer radical polymerization (ATRP), reversible addition-fragmentation chain transfer (RAFT), and nitroxide-mediated polymerization (NMP) are critically evaluated for their precision and flexibility in polymer design. Significant applications in smart separation, carbon capture, drug delivery, desalination, emulsions, tissue engineering, and sensing technologies are discussed comprehensively. Although substantial progress has been made, ongoing challenges include enhancing response speed, durability, sustainability, and economic viability. Future research is recommended to focus on innovative polymer structures, computational modeling, hybrid materials, and greener synthesis methods. This review aims to inspire continued exploration and practical utilization of CO₂-responsive polymers to address pressing environmental and technological needs.

Rising CO2 emissions and the need for sustainable energy solutions have sped up research into CO2 methanation, a catalytic process that changes CO2 into methane, an energy carrier that can be stored and used in many ways. Zeolite-based catalysts have shown a lot of promise for CO₂ methanation because they have unique pore structures, can handle high temperatures up to 400°C, and can support metal dispersion. This makes them perfect for producing methane selectively and efficiently. This review brings together the latest progress in zeolite-catalyzed CO2 methanation. It gives a thorough look at the different types of catalysts, their structural properties, and how different metal modifications affect their ability to work as a catalyst. We examine key zeolite frameworks, including ZSM-5, Beta, and FAU, comparing their activity, selectivity, and stability under diverse reaction conditions. Additionally, we explore mechanochemical synthesis and hybrid catalyst designs that enhance CO₂ conversion efficiency. By summing up what is known so far and pointing out good catalyst properties, this review shows how to improve CO₂ methanation using zeolite-based catalysts and suggests areas for future research on high-performance, scalable systems for using carbon and storing renewable energy.