Hierarchical nano-ZSM-5 zeolites (Z5-X) with different grain sizes were synthesized by varying amounts of 3-glycidoxypropyltrimethoxysilane (KH-560) in the hydrothermal synthesis strategy. Moreover, the conventional ZSM-5zeolite(Z5), which was prepared without KH-560, was used as the reference sample. The crystalline phases, morphologies, porous characteristics, Si/Al molar ratios and acidic properties of all fresh catalysts were characterized using the X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), scanning electron microscopy (SEM), N₂ adsorption–desorption, inductively coupled plasma atomic emission spectroscopy (ICP) and temperature programmed desorption of ammonia (NH₃-TPD) techniques. Results show that the grain size and strong acid amount of zeolite decreased with the increasing amount of KH-560. The micropore surface areas and the corresponding volume of Z5-X changed less compared with Z5. Consequently, the high shape-selectivity of zeolite was preserved well under the addition of KH-560. However, the mesopore surface areas and the corresponding volume increased significantly with the increasing amount of KH-560. Benefiting from the abundant hierarchical structure, the Z5-X catalysts exhibited a larger coke capacity than the Z5 catalyst. The coke depositions of all the deactivated catalysts were characterized by the thermogravimetric technique (TG), and the results are indicative of the decreased average rate of coke deposition with an increasing amount of KH-560, which could result from the gradually reduced strong acid amount and the nano-sized crystallites. The catalytic performance of methanol-to-aromatics (MTA) indicates that the Z5-0.12 catalyst exhibited higher catalytic activity and selectivity of BTX as the reaction was prolonged, which could result from the synergistic effect among the proper strong acid amount, the smaller zeolite grain size, and the abundant hierarchical structure.

Cu can prevent carbon deposition on a surface due to weak adsorption, but it exhibits a high energy barrier to C–H bond activation, which means that it is not practical. Here, inspired by the catalytic properties of Pt and the strategy of single-atom alloys, a Pt₁Cu single-atom alloy (SAA) catalyst is built and studied. The primary goal is to understand the alloy's catalytic activity and coke-resistant properties during the partial oxidation of methane (POM) using density functional theory (DFT). Based on the wide application of Ni-based catalysts in POM, a parallel sample using a Pt₁Ni SAA catalyst is also studied. C–H bond activation and coke resistance are quantified by the activation energy barrier of CH₄ dissociation and the energy barrier of C₂ formation, respectively. It is shown that the Pt₁Cu SAA catalyst can promote activation of the C–H bond of CH₄, without affecting the excellent coke resistance. The first C–H cleavage is promoted by the introduction of a Pt single atom, and the activation energy barrier is 1.73 eV on the Cu(111) surface, while it is 1.16 eV on the Pt₁Cu(111) surface. The activation energy barrier of C₂ formation is 2.08 eV on the Cu(111) surface and 1.89 eV on the Pt₁Cu(111) surface. The properties of the Pt single-alloy Cu catalyst are obviously enhanced compared with reactions on commercial Ni-based catalysts. The activation energy barrier is 1.10 eV for CH₄ dissociation and 1.35 eV for C₂ formation with the Pt₁Ni SAA catalyst. Coke resistance is further elucidated by the method of changes of partial density of states (PDOS) and Mulliken charges in this work. The results on the electronic properties are consistent with the thermodynamic results. A reference strategy is provided in this work to promote the activation of the C–H bond and the coke-resistant performance during POM.

Selective conversion of syngas (CO/H₂) to ethanol is an attractive but challenging target.

Atomically dispersed Pt atoms encapsulated inside ZSM‐5 zeolites are synthesized via thermally induced dispersion under oxygen atmosphere. Dispersion of Pt clusters within ZSM‐5 and silicate‐1 is compared to investigate its dependence on the support and calcination temperature. Detailed density functional theory (DFT) calculations are applied to rationalize the dispersion process, which includes the detachment of Pt species from the bulk and the migration of volatile PtO _x species, both of which are accelerated by thermal treatment at high temperature. DFT results also indicate that Al atoms within zeolites provide the anchoring sites to retain the dominated PtO species, though their interaction with the support is weakened with the increase in temperature. Our findings suggest that successful dispersion depends on the strong metal–support interaction and thermal treatment at moderate temperature (500 °C) which is crucial to balance the detachment and fixation of Pt atoms. This study paves the way to further understand the dispersion mechanism and assist in the development of stable single‐atom catalysts.

The supporting modes of active metal over mesoporous materials play an important role in catalytic performance. The location of Ni nanoparticles inside or outside the mesoporous channel of MCM-41 has a significant influence on the reactivity in partial oxidation of methane to syngas reaction. The characterization data using different techniques (Transmission Electron Microscope (TEM), X-Ray Diffraction (XRD), N₂ adsorption-desorption, H₂ Temperature-Programmed Reduction (H₂-TPR), and Inductively Coupled Plasma (ICP)) indicated that nickel was located outside the mesoporous channels for the impregnation method (Ni/MCM-41), while nickel was encapsulated within MCM-41 via the one-step hydrothermal crystallization method (Ni-MCM-41). The nickel atoms were mainly dispersed predominantly inside the skeleton of zeolite. When the load amount of Ni increased, both of Ni species inside the skeleton or pore channel of zeolite increased, and the ordered structure of MCM-41 was destroyed gradually. Contributed by the strong interaction with MCM-41, the Ni particles of Ni-MCM-41 were highly dispersed with smaller particle size compared with supported Ni/MCM-41 catalyst. The Ni-MCM-41 displayed higher catalytic performance than Ni/MCM-41, especially 10% Ni-MCM-41 due to high dispersity of Ni. The confinement effect of MCM-41 zeolite also afforded high resistance of sintering and coking for 10% Ni-MCM-41 catalyst. Especially, 10% Ni-MCM-41 catalyst showed outstanding catalytic stability.