Electrified non-thermal plasma (NTP) catalytic hydrogenation is the promising alternative to the thermal counterparts, being able to be operated under mild conditions and compatible with green electricity/hydrogen. Rational design of the catalysts for such NTP-catalytic systems is one of the keys to improve the process efficiency. Here, we present the development of siliceous mesocellular foam (MCF) supported Cu catalysts for NTP-catalytic CO₂ hydrogenation to methanol. The findings show that the pristine MCF support with high specific surface area and large mesopore of 784 m²·g⁻¹ and ~8.5 nm could promote the plasma discharging and the diffusion of species through its framework, outperforming other control porous materials (viz., silicalite-1, SiO₂, and SBA-15). Compared to the NTP system employing the bare MCF, the inclusion of Cu and Zn in MCF (i.e., Cu₁Zn₁/MCF) promoted the methanol formation of the NTP-catalytic system with a higher space-time yield of methanol at ~275 μmol·g_cat⁻¹·h⁻¹ and a lower energy consumption of 26.4 kJ·{\mathrm{m}\mathrm{m}\mathrm{o}\mathrm{l}}_{{\mathrm{C}\mathrm{H}}_3\mathrm{O}\mathrm{H}}⁻¹ (conversely, ~225 μmol·g_cat⁻¹·h⁻¹ and ~71 kJ·{\mathrm{m}\mathrm{m}\mathrm{o}\mathrm{l}}_{{\mathrm{C}\mathrm{H}}_3\mathrm{O}\mathrm{H}}⁻¹, respectively, for the bare MCF system at 10.1 kV). The findings suggest that inclusion of active metal sites (especially Zn species) could stabilize the CO₂/CO-related intermediates to facilitate the surface reaction toward methanol formation.

Bifunctional metal/zeolite materials are some of the most suitable catalysts for the direct hydroalkylation of benzene to cyclohexylbenzene. The overall catalytic performance of this reaction is strongly influenced by the hydrogenation, which is dependent on the metal sizes. Thus, systematically investigating the metal size effects in the hydroalkylation of benzene is essential. In this work, we successfully synthesized Ru and Pd nanoparticles on Sinopec Composition Materials No.1 zeolite with various metal sizes. We demonstrated the size-dependent catalytic activity of zeolite-supported Ru and Pd catalysts in the hydroalkylation of benzene, which can be attributed to the size-induced hydrogen spillover capability differences. Our work presents new insights into the hydroalkylation reaction and may open up a new avenue for the smart design of advanced metal/zeolite bi-functional catalysts.

We report results from computational modeling of the relative stability of germanosilicate SCM-15 structure due to different distribution of germanium heteroatoms in the double four-member rings (D4Rs) of the framework and the orientation of the structure directing agent (SDA) molecules in the as-synthesized zeolite. The calculated relative energies of the bare zeolite framework suggest that structures with germanium ions clustered in the same D4Rs, e.g., with large number of Ge–O–Ge contacts, are the most stable. The simulations of various orientations of the SDA in the pores of the germanosilicate zeolite show different stability order—the most stable models are the structures with germanium spread among all D4Rs. Thus, for SCM-15 the stabilization due to the presence of the SDA and their orientation, is thermodynamic factor directing both the formation of specific framework type and Ge distribution in the framework during the synthesis. The relative stability of bare structures with different germanium distribution is of minor importance. This differs from SCM-14 germanosilicate, reported earlier, for which the stability order is preserved in presence of SDA. Thus, even for zeolites with the same chemical composition and SDA, the characteristics of their framework lead to different energetic preference for germanium distribution.

The fabrication of suitable MFI zeolites to effectively produce para-xylene through the alkylation between toluene and methanol is highly desired. Here, the two-dimensional pillared MFI zeolite was modified by silicalite-1, and its morphology and structure were systematically investigated by tuning the concentration of Si species during the secondary crystallization process. The MFI zeolites were characterized by X-ray diffraction, transmission electron microscopy, pyridine-infrared and N₂ adsorption-desorption isotherms. The characterization results showed that the external Brønsted acid sites of surface passivated P-MFI-x samples have been successfully shielded. Interestingly, the P-MFI-23 showed long lifetime and high selectivity of para-xylene (about 35%) based on the cooperation between opened interlamellar structure and passivated silicalite-1 layer. It was found that the accumulated hard coke in the interior of MFI zeolites not only blocked the channels of zeolites but also covered the acidic sites, resulting in the deactivation of catalyst. Furthermore, the highest selectivity of para-xylene (about 48%) can be achieved for P-MFI-30 under harsh reaction condition, which also exhibited excellent regeneration property in the alkylation reaction between toluene and methanol. The strategy described in present research may open a window for the design of other advanced materials.