Catalysis Communications最新文献

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.

This study's objective is to examine the potential of the chitosan-supported Ag and Ag₂O nanoparticles on the reduction of CO₂. The transition state of the reduction reaction was systematically calculated using the nudged elastic band and the semi-empirical tight-binding calculations. It is found that the large charge polarization on the Ag and Ag₂O nanoclusters can modulate chitosan's surface reactivity. The formation of the metal hydrates is the rate-determining step for reducing CO₂. The calculated activation energy of the order of 1.5 eV demonstrates that Ag and Ag₂O /chitosan could be used as catalysts for converting to CO₂ formic acid_.

Molybdenum disulfide /reduced Graphene Oxide /Polyaniline nanocomposites (NCs) was prepared via a two-step synthesis procedures involving hydrothermal and in-situ chemical polymerization techniques. The morphological analysis revealed a well-interconnected structure. X-ray diffraction and Raman spectroscopy revealed the effective formation of the nanocomposites, while Ultraviolet-diffuse reflectance spectroscopy demonstrated enhanced visible light absorption. The degradation rates were up to 96.59% for Methylene Blue, 70.24% for Rhodamine Blue, and 46.03% for Methyl Orange under sunlight light irradiation. The antimicrobial activity of the NCs against various strains, including Escherichia coli, Candida Albicans, and Staphylococcus aureus showed that the prepared nanocomposite possesses better effectiveness against Candida Albicans.

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.

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.

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.

This study proposes a new approach for the efficient photodegradation of polycyclic aromatic hydrocarbons (PAH) and derivatives. PAH removal was achieved in just a few minutes using a microwave photochemical reactor capable of producing a high concentration of ^•OH (2.3 mmol L⁻¹ h⁻¹). Fluorescence excitation-emission matrix (EEM) spectroscopy coupled to parallel factor analysis (PARAFAC) was used for quantifying two PAH and one alkylated PAH at low concentrations (μg L⁻¹). These results highlight the high potential of the photochemical degradation system coupled to EEM-PARAFAC as an alternative fast, inexpensive, and efficient approach for environmental remediation studies of PAH.

The advancement of extremely effective and long-lasting sustainable electrocatalysts developed from abundant earth elements is an emergence aspect in green energy generation. The greenly synthesised NCF-LDH has been shown that promising candidate for the OER process. Mechnochemical processes are often quick, inexpensive, and easily scalable to produce industrial quantities. In comparison with IrO₂ (370 mV), the optimum NCF-LDH-X on GC electrode showed the modest required overpotential (240 mV) at 10 mA cm⁻². Solar-assisted water oxidation at 1.57 V shows more expert efficacy of NCF-LDH-2 for solar to hydrogen generation. As an outcome, the greenly synthesised NCF-LDH outperformed the high-priced electrocatalysts. Consequently, low-cost industrial-scale H₂ generation using commercial solar cells might be possible.

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 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.