Recent Advances in Bimetallic Catalysts for Methane Steam Reforming in Hydrogen Production: Current Trends, Challenges, and Future Prospects.

As energy demand continues to rise and the global population steadily grows, there is a growing interest in exploring alternative, clean, and renewable energy sources. The search for alternatives, such as green hydrogen, as both a fuel and an industrial feedstock, is intensifying. Methane steam reforming (MSR) has long been considered a primary method for hydrogen production, despite its numerous advantages, the activity and stability of the conventional Ni catalysts are major concerns due to carbon formation and metal sintering at high temperatures, posing significant drawbacks to the process. In recent years, significant attention has been given to bimetallic catalysts as a potential solution to overcome the challenges associated with methane steam reforming. Thus, this review focuses on the recent advancements in bimetallic catalysts for hydrogen production through methane steam reforming. The review explores various aspects including reactor type, catalyst selection, and the impact of different operating parameters such as reaction temperature, pressure, feed composition, reactor configuration, and feed and sweep gas flow rates. The analysis and discussion revolve around key performance indicators such as methane conversion, hydrogen recovery, and hydrogen yield.

Biodiesel Production from Waste Cooking Oil via ß-Zeolite-Supported Sulfated Metal Oxide Catalyst Systems.

Waste cooking oil (WCO) is a readily available and cheap feedstock for biodiesel production. However, WCO contains high levels of free fatty acids (FFAs), which negatively impact the biodiesel yield if homogeneous catalysts are used. Heterogeneous solid acid catalysts are preferred for low-cost feedstocks because the catalysts are highly insensitive to high levels of FFA in the feedstock. Therefore, in the present study, we synthesized and evaluated different solid catalysts, pure ß-zeolite, ZnO-ß-zeolite, and SO42-/ZnO-ß-zeolite for the production of biodiesel using WCO as feedstock. The synthesized catalysts were characterized by Fourier transform infrared spectroscopy (FTIR), pyridine-FTIR, N2 adsorption-desorption, X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy, while the biodiesel product was analyzed using nuclear magnetic resonance (1H and 13C NMR) and gas chromatography-mass spectroscopy. The results revealed that the SO42-/ZnO-ß-zeolite catalyst showed excellent catalytic performance for simultaneous transesterification and esterification of WCO, with a higher percentage conversion than the ZnO-ß-zeolite and pure ß-zeolite catalyst, due to the large pore size and high acidity. The SO42-/ZnO-ß-zeolite catalyst exhibits 6.5 nm pore size, a total pore volume of 0.17 cm3/g, and high surface area of 250.26 m2/g. Experimental parameters such as catalyst loading, methanol:oil molar ratio, temperature, and reaction time were varied in order to establish the optimal parameters. The highest WCO conversion of 96.9% was obtained using the SO42-/ZnO-ß-zeolite catalyst under an optimum reaction condition of 3.0 wt % catalyst loading, 200 °C reaction temperature, and 15:1 molar ratio of methanol to oil in 8 h reaction time. The WCO-derived biodiesel properties conform to the ASTM6751 standard specification. Our investigation of its kinetics revealed that the reaction follows a pseudo first-order kinetic model, with an activation energy (Ea) of 38.58 kJ/mol. Moreover, the stability and reusability of the catalysts were evaluated, and it was found that the SO42-/ZnO-ß-zeolite catalyst exhibited good stability, giving a biodiesel conversion of over 80% after three synthesis cycles.

Hierarchical Hybrid Supports and Synthesis Strategies for Hydrodesulfurization of Recalcitrance Organosulfur Compounds.

It is undisputed that there is a paradigm shift in the global trend of crude oil towards being more sour and heavier than usual light sources. Consequently, the hydrotreating activity becomes a bottleneck with high content of S, N, metals and other impurities than expected. On the other hand, the price of petroleum products lately witnessed instability and fell to the lowest average price (

4-phenyl-1,2,3-triazole functionalized mesoporous silica SBA-15 as sorbent in an efficient stir bar-supported micro-solid-phase extraction strategy for highly to moderately polar phenols.

A simple and effective strategy for the extraction of highly to moderately polar phenols in water samples was developed by synthesizing a series of 4-phenyl-1,2,3-triazole functionalized SBA-15 sorbents (xN3-Ph-SBA-15; x = 2 - 10 wt%) via two steps: azide functionalization of SBA-15 and its click reaction with phenylacetylene. The formed sorbents, which have a blend of both polar (1,2,3-triazole) and non-polar (long chain alkyl groups) sites were characterized using magic angle spinning NMR, surface area, pore size/pore volume N2 adsorption-desorption isotherms, scanning electron microscopy, and Fourier transform infrared spectroscopy. The surface area and pore size/pore volume were seen to decrease with increasing loading of 4-phenyl-1,2,3-triazole. The sorbents were used in a stir bar-supported micro-solid-phase extraction (SB-µ-SPE) for seven selected phenols in 10 mL water samples, and in combination with gas chromatography - mass spectrometry (GC-MS). A wide number of parameters were studied in the method optimization: 10N3-Ph-SBA-15 was the best sorbent which performed better using 20 mg dosage; 15 min extraction time; 300 µL of ethyl acetate as desorption solvent, 20 min desorption time; and ionic strength set at 0.5 g NaCl. The approach provided the desired linearity range for all tested phenols with R2 value up to 0.9989 and detection limit (LOD) of 0.23-0.37 ng mL-1. Relative standard deviation (RSD) and relative recovery experiments were tested using phenols spiked at 1, 100 and 400 ng mL-1. RSD values were calculated in the range of 2.3-7.5% and the relative recoveries in the wastewater matrix successfully presented a range of 88.5-99.2%.