Catalysis Communications最新文献

Several tertiary amine solutions with different structures were tested in the integrated CO₂ capture and hydrogenation process in the presence of heterogeneous Pd/NAC catalysts. The tertiary amines of 3-dimethylamino-1,2-propanediol (3DMA-1,2-PD) and 3-diethylamino-1,2-propanedio (3DEA-1,2-PD) with high CO₂ absorption capacity and high formate yield were selected as suitable candidates as CO₂ capture and hydrogenation solvents. Under mild reaction conditions, a high formate yield of 68% was achieved when using 1 M 3DMA-1,2-PD solution with CO₂ loading of 0.5 mol amine/mol CO₂. In addition, the physico-chemical properties of the Pd/NAC catalysts were examined and the reaction mechanism of CO₂ absorption and hydrogenation in the presence of Pd/NAC was proposed.

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.

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.

Utilising additive manufacturing (AM), reactors with composite structures, featuring locally tuned geometries and controlled porosity, can effectively be employed in chemical reactions. This innovation yields enhancements in flow and transport properties across both axial and transverse dimensions. Integrating structured catalysts with AM offers great potentials, albeit faces notable challenges. A significant challenge is scarce availability of suitable high-temperature materials for AM of catalytic converters. Furthermore, ensuring optimal adhesion and chemical interactions between catalyst systems and printed materials necessitates detailed investigations. This paper examines advantages and challenges associated with AM of structured catalytic converters, employing emission control systems as an illustration.

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.

The photoreforming of polyethylene terephthalate and bisphenol A was here investigated using uncommon photocatalysts (SiC-g-C₃N₄ composites). The results showed as the addition of small amounts of g-C₃N₄ on SiC promoted an efficient charge carriers separation and a good interaction between the two materials, leading to a H₂ production rate of 18 and 12 μmolH₂/g_cat∙h for the photoreforming of polyethylene terephthalate and bisphenol A, respectively. The accurate selection of different g-C₃N₄ precursors, combined with the appropriate control of the key reaction parameters (pH and plastic materials pretreatments) allowed to optimize the performance of the SiC-g-C₃N₄ composites for the photocatalytic H₂ production.

This work reports for the first time the photochemical transformation suffered by the UiO-66-NH₂ MOF during hydrogen production under solar irradiation using different scavengers. Triethanolamine caused the complete dissolution of the MOF, while Na₂S/Na₂SO₃ transformed the UiO-66-NH₂ into a novel Zr-based material characterized by an amorphous structure with a production rate of 0.439 μmol H₂·g_cat⁻¹·h⁻¹. The MOF-derived material maintained its performance during long-term on-stream experiments thanks to the electron transfer from the sulfide/sulfite ions to the valence band of the photocatalyst. However, significant doubts about the stability of UiO-66NH₂ and other MOFs in the photocatalytic generation of hydrogen are arisen.

This study focuses on the synthesis of hierarchical nano-sized beta zeolites that exhibit enhanced catalytic properties through zeolite particle size reduction (to <80 nm) and the introduction of mesopores inside and between particles to improve diffusion of large molecules. The zeolites were produced by desilication and with template-including nano-sized beta as starting material. The samples were characterized by BET, XRD, XRF, solid-state NMR, TG-DTA, and NH₃-TPD. Our method uses a shortened synthesis process to yield zeolites with higher surface area, pore volume (>1.0 ml/g), and stronger acidity that those developed by other methods. The zeolite reaction performances were evaluated in crude oil hydrocracking under commercial hydrocracker operating conditions in a pilot plant unit. The testing results showed that the catalyst including the hierarchical nanosized zeolite beta had much higher heavy oil conversion activity and naphtha selectivity.

Constructing a heterojunction is an effective strategy to achieve high-efficiency separation of charges, which enhances the photocatalytic performance. Here, we present a 0D/3D S-scheme heterojunction, BiOBr/Bi₇O₉I₃, which was constructed by incorporating highly dispersed BiOBr quantum dots (QDs) onto the surface of Bi₇O₉I₃ nanoflowers. This heterostructure effectively absorbs visible light and enhances the separation of charge carriers significantly via an S-scheme pathway. As a result, the BiOBr/Bi₇O₉I₃ photocatalysts demonstrated an excellent photocatalytic O₂ evolution rate, achieving a rate of nearly 1500 μmol h⁻¹ g⁻¹. This work highlights the effectiveness of constructing S-scheme heterojunctions to enhance photocatalytic O₂ evolution.

This work investigates the stability and regeneration of HZSM-5 and Ni/HZSM-5 catalysts in the ethanol-to-hydrocarbon conversion. The catalysts were characterised using different techniques and evaluated at 623 K and 7 h⁻¹ for 96 h TOS with two regeneration cycles. HZSM-5 showed high stability with 100% ethanol conversion, while Ni/HZSM-5 catalysts maintained 100% stability for 48 h before dropping. Regenerated catalysts were comparable to the originals in terms of product distribution, stability, and performance. HZSM-5 preferred BTX, while Ni-doped catalysts favoured C₅-C₈, C₉-C₁₂, and C₁₂+ synthesis. The regeneration process restored catalytic activity, especially for the Ni-doped catalysts, extending their life and reducing replacement costs.