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.

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.

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.

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.

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.

The basic theme of the current research work is based on the utilization of waste materials to produce environmentally friendly energy, i.e., waste + waste = energy. Efficacious and recyclable eggshell derived CaO, and transition metal doped CaO i.e. Fe-CaO, and Ni-CaO catalysts were used to synthesize biodiesel from chicken fat as a potential source of bioenergy. The synthesized catalysts were examined using a variety of analysis methods, such as FTIR, SEM, and XRD. Single step transesterification process gave 83% biodiesel yield using Fe-CaO. The characteristics of synthesized biodiesel were compared with international standards (ASTM6751 and EU14214).

This study introduces a novel green synthesis method using Hyphaene Thebaica fruit extracts to produce WO₃ nanoflakes. The synthesized material exhibits remarkable visible light photocatalytic efficiency in degrading Methylene Blue (MB) and Congo Red (CR) pollutants. With removal efficiencies exceeding 98% for MB and 93% for CR within short durations, the WO₃ nanoflakes show promise for water treatment. Trapping experiments suggest that hydroxyl radicals, hydrogen peroxide, and holes are the primary reactive species involved in the photodegradation process. Additionally, the recyclability study demonstrates the stability and reusability of WO₃ nanoflakes, further highlighting their potential for practical applications in wastewater treatment.

In this study, La-doped ZrO₂/g-C₃N₄ nanocomposites were synthesized and remarkably, 0.8% La-doped ZrO₂/g-C₃N₄ exhibited an outstanding degradation efficiency of 87% (k = 11.301 × 10⁻³ min⁻¹). The enhanced photocatalytic performance is due to the synergistic effects of lanthanum and g-C₃N₄, which promote charge separation and increase the number of active sites. A built-in electric field exists according to the charge density difference and electrostatic potential results. At 300 K, the nanocomposite is thermally, energetically, and dynamically stable. Our results provide valuable insights into the design and development of efficient photocatalysts for the removal of organic contaminants from aqueous environments.

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.