Catalysis Communications最新文献

Zeolite with nanoscale in some dimensions always display better catalytic performance because it contains more exposed catalytic active sites. Herein, a Cu²⁺ exchanged SSZ-39 zeolite with nanosheet morphology was chosen as a catalyst for the preparation of 2-vinyl heterocycle ethers through decarboxylative cross-coupling of cinnamic acids with ethers. The template reaction conditions were optimized, and the possible reaction mechanism was proposed. Then, a wide range of 2-vinyl heterocycle ethers were prepared. The recycling experiment demonstrated the good sustainability of the catalyst. The potential value of the catalytic product was demonstrated through the bifunctional addition and hydrogenation reduction.

5 wt% ruthenium-loaded Zeolite-β is found to be efficient for hydrotreating the lignin model compound, m-cresol, at 170 °C under 10 bar hydrogen pressure to give methyl cyclohexane. The catalyst has a bifunctional nature in which the redox properties of ruthenium and the strong acidic nature of Zeolite-β are instrumental in the hydrotreating of m-cresol. The well-dispersed metallic ruthenium on Zeolite-β, as evident from TEM and EDS mapping analysis, is responsible for the potential activity. The activity was retained even after six cycles and was also found to have potential for hydrotreating various other functional substrates.

A high-pressure hydrothermal method was employed to introduce Ce element facilely into MoVTeNbO_x catalysts in 0.5 h. It was indicated that Ce atoms were doped into the framework of MoVTeNbO_x without changing the unique crystal structure of MoVTeNbO_x. The introduction of Ce could facilitate the formation of oxygen vacancies and improve the redox ability of surfacial V. However, it was worth noting that the doping amount of Ce was negatively related to the content of M1 active phase. Within a certain range, the catalytic performance could be improved by sacrificing an appropriate amount of M1 phase. In the conversion of propylene to acrylic acid, the highest yield of 58.2% was obtained under catalyst MoVTeNbCeO_x (V: Ce =1: 0.05) at 380 °C with the M1 phase content of 81.6%. The appropriate amount of Ce doping improved the propylene conversion by more than 20% compared to undoped. Moreover, the changes in Gibbs free energy of the rate-limiting step of direct oxidation of propylene before and after Ce doping were evaluated by Density functional theory (DFT). It is illustrated that the doping of Ce is thought to affect the main reason for the reduction of Gibbs free energy.

Unactivated bean sprout (Faba pullulat) biochar (BSB) supported cadmium sulfide composites (CdS/BSB) were prepared by hydrothermal combined with freeze-drying without adding any activation agent. The structure and morphology have been characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) in detail, respectively. CdS/BSB(5:4) with a mass ratio of CdS to BSB of 5:4 had the highest photocatalytic hydrogen production rate of 17.7 mmol.g⁻¹.h⁻¹, which is about 3.93 and 3.2 times that of synthesized CdS without biochar and the commercial activated carbon supported CdS, respectively. These results suggested that biochar derived from bean sprout could be a low-cost, renewable, environmentally friendly and metal-free cocatalyst for hydrogen generation.

Water pollution caused by antibiotics poses a serious threat to human health and ecosystems. Rapid and efficient removal of antibiotic pollution in water by photocatalysts is one of the effective means to protect the environment and public health. Herein, a wide-spectral responsive upconversion NaGdF₄:Yb,Tm@Mn-MOFs core-shell nanostructures were built by coating hexagonal NaGdF₄:Yb,Tm cores with amino-functionalized manganese carboxylate MOFs (Mn-MOFs) shells, which exhibited good water dispersibility. Mn-MOFs catalysts is mainly concentrated in the ultraviolet region, while NaGdF₄:Yb,Tm nanoparticles can transform infrared light into visible light or even higher energy ultraviolet light, which is harvested by the Mn-MOFs. The optimized nanostructures were tested under simulated solar light (After 120 min irradiation) in the degradation of tetracycline, oxytetracycline hydrochloride and tetracycline hydrochloride, while their degradation rates reached 70%, 72% and 75%, respectively. The better photocatalytic mechanism for antibiotics than its individual components was elucidated, which provides a potential strategy to broaden the full spectrum absorption of the wide bandgap semiconductors and apply for the field of environmental remediation.

A novel Deep Eutectic Solvent (ChCl/THFTCA-DES) was prepared by a mixture (2:1) of choline chloride [(CH₃)₃N⁺CH₂CH₂OH]Clˉ = (ChCl) and tetrahydrofuran-2,3,4,5-tetracarboxylic acid (THFTCA) as a cheap, simple, and non-toxic method, characterized by FT-IR, densito-meter, eutectic point, and ¹H NMR techniques and used as a capable and new catalyst for the synthesis of ten Henna-based benzopyranophenazine‑carbonitriles.

Lattice strain and ligand effects of core-shell structure regulate the geometric and electronic properties of the active metal on the surface of catalysts. Herein, a core-shell Ni/CeO₂@Al₂O₃ catalyst was prepared by hydrothermal deposition for selective hydrogenation of acetylene. Compared with the general Ni/Al₂O₃ catalyst, the ethylene selectivity of the Ni/CeO₂@Al₂O₃ catalyst was significantly improved due to the special structure reduced the adsorption strength of ethylene. Under the condition of 10% CeO₂ loading, the performance of the catalyst was the best (85.3% C₂H₂ conversion and 81.2% C₂H₄ selectivity). This work provided a new approach for exploring efficient catalysts for semi‑hydrogenation reaction.

Lime (Citrus aurantifolia) is one of the most extensively exported agricultural products from Indonesia. Citric acid and ascorbic acid content from limes (Citrus aurantifolia) is such one of the carbon-rich fruits that is a suitable source for Carbon Quantum Dots (CQDs) synthesis. CQD synthesized by relying on natural carbon precursors from lime (Citrus aurantifolia) is a more environmentally friendly approach in the present research, CQDs in this research will be used as an addition to ZnO by hydrothermal method in order to enhance photocatalytic activity. Corresponding to the results, the presence of CQDs improves both the optical and structural properties of ZnO, which led to enhance photocatalytic activity with a degradation percentage of 98% shortly after 75 min of visible light irradiation and to each of the repeatability test cycle results showing the consistent results and with the rate constant (k) fluctuating and the specified compound's degradation percentage remains relatively constant with minor changes.

A strategy to mitigate diffusion restrictions associated with heavy crude oil conversions is using mesostructured Y zeolite. In recent years, multiple routes have been proposed for obtaining materials with improved catalytic performance versus catalysts with higher molecular transport restrictions. Typically, after the implementation of these treatments, improvement in catalytic activity is correlated either with changes in textural properties (area and porous volume) or the modification of physicochemical properties (Si/Al ratio and acid strength); however, the correlation with diffusional mass transport characteristics is not typical. In this study, alkylaromatic molecules of different kinetic diameters, such as benzene, toluene, p–xylene, and m–xylene, were used as molecule probes to determine the effective diffusion through a pulse experiment under conditions of no adsorption or reaction. The studied solids include five commercial zeolites from the Zeolyst CBV series and four top–down mesostructured Y zeolites. The obtained concentration curves were fitted to an exponential decay model, a solution of the second Fick's law under defined experimental conditions, and correlation values between 0.9996 > R² > 0.9896 were found. Furthermore, the implementation of the descriptors “Transport ratio (TR_MR)” and “Corrected transport ratio (TR_MR^c)” was proposed, which allowed the combined representation of the change in the mass transport of aromatic probes and the changes in the acidity of the zeolite, after the application of top–down treatments. These descriptors proved simple and effective tools to correlate the changes after mesopore insertion with the catalytic performance in the 1,3,5–Triisopropylbenzene (TIPB) cracking reaction. Our approach is an integral method of screening mesostructured zeolites with an adequate balance of acidity and transport properties.

Growing concerns regarding the inefficient degradation of persistent pollutants, such as ibuprofen, in water necessitate the development of advanced treatment methods. Nb₂O₅, with its properties resembling those of TiO₂, emerges as a promising alternative catalyst for advanced catalytic treatments. In this work, we demonstrate the exceptional catalytic ozonation and photocatalysis performance of Nb₂O₅/MWCNT nanocomposites synthesized via three sol-gel methods. These composites achieve complete ibuprofen degradation within 30 min, outperforming conventional catalysts and ozonation alone due to their enhanced surface area and synergistic interactions. Nb₂O₅/MWCNT presents a compelling solution, offering an efficient and sustainable approach to water purification.