Catalysis Surveys from Asia最新文献

The investigation of the process of converting levulinic acid (LA) into ethyl levulinate (EL) using tungstic acid (TA)-functionalized activated natural zeolite (AZ) was systematically conducted. The aims of this work were to synthesize and characterize the activated zeolite modified by tungstic acid (TA-AZ) and also evaluate its performance in LA esterification. We employed the wet impregnation approach and ultrasonication-assisted method to produce TA-AZ catalyst with different concentrations of TA (15, 20, and 25 wt%). Fourier transform infrared (FTIR), ammonia-temperature programmed desorption (NH₃-TPD), X-ray diffraction (XRD), scanning electron microscope with an energy dispersive X-ray spectrometer (SEM-EDX), transmission electron microscope (TEM), and surface area analyzer (SAA) were among the analytical methods used to investigate the chemical and physical characteristics of AZ and TA-AZ catalysts. The liquid yields from LA esterification were analyzed by GC-FID. The findings indicated that the 25TA-AZ catalyst exhibited the highest acidity, reaching 3.65 mmol/g. The presence of TA in AZ resulted in an enhancement of LA conversion and an increase in EL yield. The LA esterification process, employing a 25TA-AZ catalyst with a reaction temperature of 150 °C and a weight% of 0.5 wt%, produced 91.72% for LA conversion and 82.65% for EL yield.

This study explores the use of graphene oxide (GO) modified with PyrCO-cyclo@Fe as an efficient and selective catalyst. The modification of GO with PyrCO-cyclo@Fe provides a robust platform for the synthesis of (S)-2-phenylpropanoic acid derivatives 4(a–l), facilitated by the presence of choline chloride ethylene glycol (ChCl/EGC) as the electrolyte in good to excellent yields (89–97%). The experimental results demonstrate that this catalytic system not only enhances the enantioselectivity of the carboxylation process but also improves the overall yield and efficiency. This method presents a promising approach for the production of valuable enantioenriched carboxylic acids, contributing to the development of green and sustainable catalytic processes in organic synthesis. The synthesized GO-PyrCO-cyclo@Fe electrode was examined utilizing various analytical methods, including FT-IR, CV, SEM, EDS, BET, TGA, and XPS The synthesized (S)-2-phenylpropanoic acid derivatives 4(a–l) were identified and characterized through melting point determination, FT-IR, ¹HNMR, and CHN analyses.

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Among the aquatic pollutant remediation reactions, the reduction of toxic Cr(VI) to a benign Cr(III) is of significant interest. Among the avrious remediation methods, photocatalysis is considered optimal due to its efficiency and eco-friendly nature. Therefore, the development of highly active, visible-light-responsive, and noble-metal-free photocatalysts for the elimination of toxic heavy metal ions from wastewater is highly desirable. In this study, a facile two-step method, comprising solvothermal and hydrothermal, was used to synthesize visible-light-responsive CdS/MoS₂ heterojunctions (CM-HJs). Extensive structural characterization was performed to assess the crystal structure (XRD and XPS), morphology (SEM and BET), and optical (UV-Vis) properties of the as-synthesized photocatalysts. Aquatic Cr(VI) photoreduction was conducted on these photocatalysts under visible light irradiation. The results revealed the high photocatalytic activity and photostability of CM-HJs for Cr(VI) reduction compared to the bare CdS. Among the heterojunctions, CM-10 (10 wt % MoS₂) exhibted the highest acvtivty, reducing 99.04% of Cr(VI) within 60 min. The enhanced photocatalytic activity can be attributed to its high light harvesting capability and efficient separation and transportation of the produced electron-hole pairs due to the intimate contact interfaces and matching band potentials of CdS with MoS₂. Based on the literature and experimental evidence, a photocatalytic mechanism for the photoreduction of Cr(VI) is discussed in detail. The effect of different parameters; like the amount of photocatalyst, amount of Cr(VI), and pH were also evaluated. Like other good photocatalysts, CM-10 owes good photostability and recyclability.

The present study successfully synthesized MnWO₄@g-C₃N₄ and CuWO₄@g-C₃N₄ nanocomposites which demonstrated high efficiency and recoverability as a robust catalyst for ODS of model (DBT) and real fuel oil (kerosene and diesel). The manufactured composites were thoroughly characterized using XRD, TGA, FTIR, SEM and EDX confirming its physicochemical properties. The SEM results revealed that MnWO₄ and CuWO₄ nanoparticles were well organized on the exterior of g-C₃N₄ forming interesting spherical particle morphology. Under optimized conditions, the nanocomposites MnWO₄@g-C₃N₄ and CuWO₄@g-C₃N₄ exhibited an impressive 98 and 98.5% removal of DBT, respectively from the model fuel (100 mg/L) within 180 min at a temperature of 45 °C using 1 mL of oxidant and 0.1 g of catalyst amount. Furthermore, the catalytic activity of composites was investigated for real fuel desulfurization and promising results were achieved. Moreover, the fuel properties were in accordance with ASTM specifications. The study found that the desulfurization reaction followed the pseudo 1st order kinetic models and the negative ∆G indicated a spontaneous method. The nanocomposites exhibited promising reusability as it could be used up to five times without significantly reducing their ability to desulfurize fuel oil. The study highlights its potential for practical applications in reducing sulfur content in fuel oils contributing to cleaner and environment friendly energy production and utilization.

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Industrial dyes from commercial sector are one of the major contributors to the environmental contamination. This research work mainly focuses on the elimination of synthetic cationic dye (Blue Tur-XGB B-3) through column and batch studies followed adsorption phenomenon. Various methods were employed to prepare the Zinc Oxide nanorods (ZnO) and different metal doped Zinc Oxide nanorods (Cu/ZnO, Ni(OH)₂/ZnO, α-Fe₂O₃/ZnO, GO/ZnO) as adsorbents. The synthesize nanorods were characterized by using FTIR analysis and SEM to confirmed the morphology and functional group of the prepared nano adsorbents. Followed the adsorption procedure the optimum pH for the cationic dye (Blue Tur-XGB B-3) was detected in the basic range which was 9 for ZnO (29.54 mg g⁻¹), 10 for Cu/ZnO (37.96 mg g⁻¹), 10 for Ni(OH)₂/ZnO (35.76 mg g⁻¹), 9 for α-Fe₂O₃/ZnO (31.88 mg g⁻¹), 9 for GO/ZnO (33.05 mg g⁻¹). The optimum dosage for all the prepared adsorbents were detected 0.05 g/50 mL and showed best adsorption capacity at temperature of 30 °C and 60 min of contact time. The initial concentration of dye was observed at the range of 125–150 mg L⁻¹ and best adsorption capacity was achieved at 100 mg L⁻¹ by all adsorbents. Photocatalysis experiment for determination of effect indicated the highest degradation efficiency of 90.49% for Cu doped ZnO NRs, 87.90% for Ni(OH)₂/ZnO NRs, 79.16% for α-Fe₂O₃/ZnO, 70% for ZnO/GONRs and 60.53% for ZnO NRs at 308 K for catalytic degradation of cationic dye (Blue Tur-XGB B-3). Adsorption followed both Langmuir and Freundlich isotherms for all adsorbents. Kinetic adsorption data supported Pseudo 1st and pseudo 2nd order kinetics while thermodynamics analysis indicated spontaneous and exothermic nature. Effect of surfactants, electrolytes, heavy metals and desorption were also evaluated. For column study, optimum bed height (3 cm), optimum flow rate (1.8 mL min⁻¹) and optimum inlet dye concentration (70 mg L⁻¹) were also observed for maximum adsorption of cationic dye (Blue Tur-XGB B-3). With the help of ZnO, the degradation of Blue Tur-XGB B-3 dye was also investigated. These methods are very cost effective, ecofriendly and easy to manufacture. The recycling results show that the ZnO nanostructures displayed good stability and long-term durability.

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This research used hydrothermal technique to synthesize three different morphologies of SBA-15 supports, such as rod, hexagonal prism, and spherical. Afterward, it impregnated Pt/Ce metal on the SBA-15 supports via wet-impregnation methods and investigated their NO reduction activity using the H₂-SCR technique in the temperature range of 50–450℃. The catalysts were characterized by Brunauer-Emmett-Teller (BET), X-Ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy, energy dispersive X-ray spectroscopy (SEM-EDS), Transmission electron microscopy (TEM), and Raman spectroscopy. Among the catalysts, Pt/Ce-SBA-15-rod exhibited the best performance with NO conversion of 52.23% and N₂ selectivity of more than 83.25% at 150℃. The Pt/Ce-SBA-15-rod catalysts’ activation energy (21.188 kJ-mol^− 1) was the lowest of all the catalysts. The catalysts with the highest NO conversion have the highest BET properties, surface oxygen (30.33%), Ce³⁺ (40.23%), Pt (0) (70.45%), and oxygen storage capacity.

The direct CO₂ methylation, coupling CO₂ hydrogenation with benzene ring methylation, provides a promising strategy to synthesize value-added aromatics using green hydrogen and CO₂ as C1 source. The tandem reaction promotes the conversion of CO₂ due to the consumption of in situ formed methoxy or methanol over the tandem catalyst of metal oxide and acid zeolite. This review aims to present the thermodynamics advantage and mechanistic insights of direct CO₂ methylation process. In practice, catalytic conversion and selectivity for typical tandem catalysts are still far below the thermodynamic equilibrium. The detail roles and proximity effects for metal oxide and acid zeolite are covered in order to give directions to the catalyst design and reaction condition optimization, which has been proposed to overcome the kinetic limitation for the direct CO₂ methylation development in future.

The development of novel compounds with potential anticancer activity is imperative for combating the challenges posed by cancer. In this study, a modified montmorillonite based catalyst is employed for the synthesis of 2,3-dihydroisoxazolo[5,4-d] pyrimidin-4(7 H)-ones, which are promising candidates for anticancer agents. Montmorillonite is modified using mixed metal oxides, typically Al₂O₃ and CeO₂, by a facile approach followed by standard spectroscopic and electron microscopic characterizations. It is then employed for the one-pot synthesis of a series of 2,3-dihydroisoxazolo[5,4-d] pyrimidin-4(7 H)-ones. The synthesis protocol, mediated by ultrasound, is simple, efficient, and environment friendly. The mixed metal oxide pillared montmorillonite catalyst exhibits high catalytic activity and selectivity, facilitating the formation of the desired compounds in good to excellent yields. The synthesized compounds are characterized using various spectroscopic techniques such as ¹H NMR, ¹³C NMR and mass spectrometry. Furthermore, the anticancer activity of the synthesized compounds is evaluated against a series of cancer cell lines, revealing promising cytotoxic effects. The findings of this study highlight the potential of novel 2,3-dihydroisoxazolo[5,4-d] pyrimidin-4(7 H)-ones as promising anticancer agent, warranting further investigation for their therapeutic potential.

The 1,2,4-thiadiazoles are an important class of heterocyclic compounds with a wide scope as a pesticide, fungicide, and in drug development including antimicrobial, anti-inflammatory, antituberculosis, anticancer, antihypertensive, and antifungal drugs, etc. Here, an oxidized-sulfur (sulfone) bridged two-dimensional cobalt (II) tetraphenylporphyrin covalent organic framework (Co-P) has been generated through a hydrothermal method on reacting of 5,10,15,20-Tetrakis-(4-bromophenyl)-porphyrin-Co(II) with sulfur powder in catalytic condition. The Co-P shows a favorable optical (1.98 eV) and electrochemical band gap (2.05 eV) for photocatalytic study. In a proof-on action study, the Co-P has been investigated in the oxidative cyclization of thioamide to 1,2,4-thiadiazole (yield = 93–97%) along with excellent regioselectivity, photostability as well as good recyclability (5 times). The excellent photocatalytic activity can be attributed to the presence of infused-sulfone functionality in the Co-P which is well known for its light-harvesting capability as well as the presence of a uniform microporous structure (pore size < 2 nm) with an average pore diameter of 1.80 nm and a surface area of approximately 4.23 m²g^− 1.

Creating cost-effective and efficient electrocatalysts for the sluggish oxygen evolution reaction (OER) is crucial for practical implementation of hydrogen production via water electrolysis, advancing metal-air batteries, and converting CO₂ into value-added chemicals. Transition metal hydroxides, particularly those containing iron (Fe), show promise as OER catalysts, yet the relationship between material properties and catalysis remains unclear. Recent advances in in-situ/operando approaches, notably ⁵⁷Fe Mössbauer spectroscopy, enable real-time monitoring of catalysts and reveal structural characteristics of Fe species. This review highlights case studies involving in-situ/operando ⁵⁷Fe Mössbauer techniques in Fe-involved metal hydroxide OER electrocatalysis, providing insights into Fe’s role, active sites, and catalytic mechanisms. The investigation aims to assess opportunities and challenges linked to the use of in-situ/operando Mössbauer spectroscopy, shedding light on potential advancements in this critical research area.