Glycolysis of waste PET is an environmental friendly and economical strategy to tackle plastic pollution. In this work, a series of niobium phosphate (NbOP) catalysts were synthesized and utilized in the glycolysis of waste PET to bis(2-hydroxyethyl) terephthalate (BHET). It was found that mesoporous structured NbOPTPAB (that prepared using tetrapropylammonium bromide (TPAB) as surfactant) possesses high surface area (160 m2/g), enlarged pore volume (0.221 cm3/g) and abundant Lewis acid sites (1624 mu mol/g), and it exhibited prominent activity for the selective formation of BHET monomer. The yield of BHET monomer reached 94.6 % under mild condition (195 degrees C and 2 h) even with low solvent dosage (EG/PET mass ratio in feed was 2.75). Besides, NbOPTPAB was also capable for the glycolysis of real waste PET-based products (beverage bottles, packaging films and textile fibers). The reaction mechanism of PET glycolysis over NbOPTPAB was proposed based on the characterization results of 2D 1H-13C FSLG-HETCOR NMR, GPC, XRD, SEM and LC-ESI-MS of the intermediates and remaining PET fragments in the reaction mixture.

The scanning electron microscope (SEM) is an essential tool in materials science, offering high-resolution imaging and a large depth of field for detailed surface analysis. It plays a pivotal role in characterizing material morphology, microstructure, and elemental distribution. Covalent organic framework (COF) membranes, known for their crystalline and porous structures, are a promising class of next-generation high-performance separation membranes. SEM enables direct visualization of key features of COF membranes, such as surface morphology, cross-sectional architecture, membrane thickness, and elemental composition (e.g., via energy-dispersive X-ray spectroscopy, EDS mapping). This laboratory experiment introduces a structured methodology for teaching students both the operational principles of SEM and its application in COF membrane characterization. The step-by-step instructional framework covers critical aspects including sample preparation, instrument operation, and image analysis. By following this comprehensive approach, students develop proficiency in using SEM, laying a solid foundation for future research involving COF membranes and related materials. In addition to advancing membrane characterization pedagogy, the flexibility of SEM supports the design of diverse undergraduate laboratory experiments within nanoscience and nanomaterials curricula. Through hands-on experience in nanoscale membrane analysis, students acquire practical and transferable skills applicable to real-world challenges in chemistry, materials science, and engineering.

Coupling dehydrogenation of cyclohexanol (CHOL) and hydrogenation of phenol (PhOH) for the production of cyclohexanone (CHON) was seldom reported as the separated dehydrogenation of CHOL and hydrogenation of PhOH require different active sites, varied surface acidity and opposite conditions. High-entropy layered double hydroxides (HE-LDHs) might be a promising candidate for this coupling reaction via the synergistic effect of all components and modulated acidity/basicity. In this work, a series of well-structured Ru-containing HE-LDHs were synthesized and utilized in the coupling dehydrogenation of CHOL with hydrogenation of PhOH for the first time. Characterizations revealed that the hexa-metallic Cu1Co1Mg4Ru0.2Al0.9Sc0.9(OH)16CO3 & sdot;4.8 H2O catalyst possesses large surface area (231 m2/g), enhanced acidity/basicity (254 mu mol/g acid sites and 674 mu mol/g basic sites), improved hydrogen adsorption capacity than those catalysts composed of two-, three-, four-, and five-metal components. It showed excellent activity under optimized reaction conditions (100 mmol CHOL + 5 mmol PhOH, 230 degrees C, 15 min), and the apparent conversion of PhOH reached 93.1 % with a formation rate of CHON as high as 661.5 g-CHON/g-Ru/h. Additionally, it was found that the dehydrogenation of CHOL could be accelerated when PhOH was added as a hydrogen acceptor, and hydrogen dehydrogenated from CHOL was utilized by PhOH which increased formation rate of CHON. The best hydrogen utilization achieved 86 %.

Sulfurized zero-valent iron (SZVI) is a promising material for controlling soil/groundwater halogenated hydrocarbon pollution. However, systematic studies on how various physicochemical properties of soil affect SZVI dechlorination activity are still lacking. To explore the influence of solid and soluble components on SZVI activity, this study compared the dechlorination performance of SZVI on trichloroethylene (TCE) in three different soils across five systems: SZVIwater (aqueous solution system), SZVIsoil (soil system), SZVIpre-soil (pre-adsorbed TCE soil system), SZVIex (soil extract system), and SZVIde-soil (soil system without soluble components). Additionally, the SZVI activity before and after aging in soil extract and solutions of various soluble components (within the concentration range of the soil extract) was compared, and the mechanism by which key soluble components influence the SZVI activity was explored. Results indicated that the dechlorination activity of SZVI was higher in soils compared to the performance in aqueous solution, and high soil organic matter content was the key inhibitor. The influence of soil solid-phase components on SZVI activity was significantly greater than that of soluble components. Soil particles enhanced SZVI activity by providing effective contact sites between SZVI and TCE, whereas soluble components inhibited SZVI activity by altering the physicochemical properties of its surface (e.g., NO3- and PO43-) and competing with TCE for electrons during the reaction (e.g., NO3- and Mn2+). These findings offer new critical insights for selecting and optimizing materials based on soil physicochemical properties.

Strong and lightweight materials are highly desired. Here we report the emergence of a compressive strength exceeding 2 GPa in a directly printed poly(ethylene glycol) micropillar. This strong and highly crosslinked micropillar is not brittle, instead, it behaves like rubber under compression. Experimental results show that the micropillar sustains a strain approaching 70%, absorbs energy up to 310 MJ/m3, and displays an almost 100% recovery after cyclic loading. Simple micro-lattices (e.g., honeycombs) of poly(ethylene glycol) also display high strength at low structural densities. By combining a series of control experiments, computational simulations and in situ characterization, we find that the key to achieving such mechanical performance lies in the fabrication of a highly homogeneous structure with suppressed defect formation. Our discovery unveils a generalizable approach for achieving a performance leap in polymeric materials and provides a complementary approach to enhance the mechanical performance of low-density latticed structures.

Precise and selective separation of target solutes from complex mixtures remains a critical yet challenging goal in industrial separation processes. Conventional membranes typically excel at separating either cations or anions but struggle to differentiate both simultaneously. In this study, we develop covalent organic framework (COF) membranes with vertically asymmetric charge distributions, fabricated via interfacial polymerization followed by nanosheet casting. These membranes exhibit pronounced ionic current rectification. Under single-salt conditions, the optimal membrane achieves exceptional selectivity values of H+/Mg2+ = 702 and NO3-/PO43- = 201. Remarkably, selectivity improves further in multicomponent systems. In an eight-component acid/salt mixture, the membrane demonstrates separation ratios of NO3-/PO43- = 380, NO3-/SO42- = 234, NO3-/Cl- = 11, H+/Li+ = 698, H+/Na+ = 1120, H+/K+ = 525, and H+/Mg2+ = 17182, maintaining stability for a continuous run for at least 216 h. This work introduces a robust membrane design strategy for highly selective solute separation from complex mixtures, offering valuable advancements for sustainable chemical recovery technologies.

Prussian blue (PB) is regarded as a promising cathode for sodium-ion batteries because of its sustainable precursor elements (e.g., Mn, Fe), easy preparation, and unique framework structure. However, the unstable structure and inherent crystal H2O restrain its practical application. For this purpose, a self-constructed trace Mg2+/K+ co-doped PB prepared via a sea-water-mediated method is proposed to address this problem. The Mg2+/K+ co-doping in the Na sites of PB is permitted by both thermodynamics and kinetics factors when synthesized in sea water. The results reveal that the introduced Mg2+ and K+ are immovable in the PB lattices and can form stronger K‒N and Mg‒N Coulombic attraction to relieve phase transition and element dissolution. Besides, the Mg2+/K+ co-doping can reduce defect and H2O contents. As a result, the PB prepared in sea water exhibits an extremely long cycle life (80.1% retention after 2400 cycles) and superior rate capability (90.4% capacity retention at 20 C relative to that at 0.1 C). To address its practical applications, a sodium salts recycling strategy is proposed to greatly reduce the PB production cost. This work provides a self-constructed Mg2+/K+ co-doped high-performance PB at a low preparation cost for sustainable, large-scale energy storage.

Zeolite-based materials play critical roles to develop new technologies toward renewable energy and environmental improvement to face the global sustainability from rapid industrial development and population increase in the new century. In the past decade, novel approaches for the preparation of zeolites have been designed from the concept of green chemistry, and new insights on zeolites frameworks have been revealed by the new techniques. Furthermore, the wettability of zeolite and consequent sorption/diffusion were demonstrated as important roles in the catalytic processes, which are quietly different from the classical behaviors of zeolites. We believe that these nonclassical advances in synthesis, structure, and catalytic performance could benefit for the understanding on crystallization of zeolites and framework characters, and consequently, the design of efficient zeolite-based materials for energy and environmental improvement.

The development of catalytic systems that can activate aryl chlorides for palladium-catalyzed cross-coupling reactions is at the forefront of ongoing efforts to synthesize fine chemicals. In this study, a facile ligand-template approach is adopted to achieve active-site encapsulation by forming supramolecular assemblies; this bestowed the pristine inert counterparts with reactivity, which is further increased upon the construction of a porous framework. Experimental results indicated that the isolation of ligands by the surrounding template units is key to the formation of catalytically active monoligated palladium complexes. Additionally, the construction of porous frameworks using the resulting supramolecular assemblies prevented the decomposition of the Pd complexes into nanoparticles, which drastically increased the catalyst lifetime. These findings, along with the simplicity and generality of the synthesis scheme, suggest that the strategy can be leveraged to achieve unique reactivity and potentially enable fine-chemical synthesis.

Direct C-H bond activation of heterocycles as a step-economical and environmentally friendly approach to build the heterobiaryls motifs is highly attractive, but it still has a challenge to design and prepare a cheap and regioselective heterogeneous catalyst. To tackle this challenge, we have introduced Ni species into a porous phenanthroline-based organic polymer donated as POP-Phen@Ni. This heterogeneous catalyst shows excellent catalytic performances in regioselective C-H activation of heterocycles, even better than those of the corresponding homogenous catalyst. H/D exchange experiments show that the lithium bis(trimethylsilyl)amide (LiHMDS), a base added in the reaction, play a very important role during the reaction processes. We believe that this heterogeneous catalyst would open a new door for design of heterogeneous catalysts to efficiently catalyze the regioselective C-H activation of heterocycles.

In this work, we present an effective strategy to enhance the reactivity and durability of molecular organometallic catalysts by constructing into porous frameworks, as demonstrated by triphenylphosphine (PPh3). Such PPh3 moieties accessible via the porous structures could be partially metalated by Pd species to generate a highly efficient and recyclable heterogeneous catalyst for the Suzuki coupling of aryl chlorides. Site isolation in the rigid framework stabilizes the catalytically active monophosphine-ligated complex against deactivation into less active assemblies of bisphosphine-Pd. Meanwhile, the densely populated free ligands inhibit the decomposition of catalytically active sites thereby highlighting the beneficial effects of such a platform. Thus, the tunability of porous polymer synthesis gives great promise to impart numerous organometallic catalysts constituted by readily available ligands with unique reactivity, which are not trivially achievable with traditional systems.

Product selectivity adjustment is a much-studied topic in mesoscience that is critical for industrial processes and strongly related to reaction intermediates formed by interactions between catalytic active sites and reactants. Herein, we report efficient adjustment of the product selectivity in the hydrogenation of substituted nitroarenes via rational reaction intermediates achieved using controllable Pd nanoparticles. Pd nanoparticles fixed within zeolite Beta crystals (Pd@Beta) afforded rational Pd-NO2 interactions, in which the Pd nanoparticle-adsorbed substituted nitroarenes, such as nitrobenzaldehyde, were reasonably hydrogenated into the corresponding aminobenzaldehyde. However, for Pd nanoparticles supported on the external surfaces of zeolite beta crystals, various side products were obtained owing to the coexistence of Pd-NO2 and Pd-C=O interactions. When Pd nanoparticles were artificially controlled in various positions in a fixed-bed reactor, the product selectivity was significantly affected. These results demonstrate the importance of molecular adsorption and diffusion processes in adjusting product selectivity in catalytic reactions. (C) 2019 Published by Elsevier B.V. on behalf of Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences.

High silica chabazite zeolite (CHA) is very important for selective catalytic reduction of NOx with ammonia (NH3-SCR), but its synthesis is time-consuming under conventional hydrothermal conditions (160 degrees C for 90-120 h). Herein, we report a novel strategy for highly efficient synthesis of CHA zeolite by means of fast crystallization at high temperatures in the absence of water solvent (240 degrees C for 1.5 h). X-ray diffraction, N-2-adsorption isotherms, inductively coupled plasma, scanning electron microscopy, Si-29 and Al-27 MAS NMR, as well as thermogravimetry-differential thermal analysis suggest that the samples have high quality. This concept significantly enhances the space-time yields (STY) for CHA zeolite prepared from high-temperature synthesis in the absence of water solvent (almost two orders of magnitude higher than those of conventional hydrothermal synthesis). Moreover, compared with hydrothermal synthesis, the samples obtained from fast crystallization at higher temperatures (Si/Al = 12, 2.0% Cu loading) shows enhanced catalytic performance at 350-550 degrees C in NH3-SCR.

With the recent emphasis and development of sustainable chemistry, the conversion of biomass feedstocks into alternative fuels and fine chemicals over various heterogeneous catalysts has received much attention. In particular, owing to their uniform micropores, strong acidity, and stable and rigid frameworks, zeolites as catalysts or co-catalysts have exhibited excellent catalytic performances in many reactions, including hydrodesulfurization, Fischer-Tropsch synthesis, and hydrodeoxygenation. However, the relatively small sizes of the zeolite micropores strongly limit the conversion of bulky biomolecules. To overcome this issue, mesoporous zeolites with pores larger than those of biomolecules have been synthesized. As expected, these mesoporous zeolites have outperformed conventional zeolites with improved activities, better selectivities, and longer catalyst lives for the upgrading of pyrolysis oils, the transformation of lipids into biofuels, and the conversion of glycerol into acrolein and aromatic compounds. This review briefly summarizes recent works on the rational synthesis of mesoporous zeolites and their superior catalytic properties in biomass conversion.

High quality CHA zeolite catalysts were efficiently synthesized by fast transformation of FAU zeolite in the absence of water.

High quality zeolite catalysts are efficiently synthesized by fast crystallization at higher temperatures under solvent-free conditions.

For human health and environmental protection, removal of formaldehyde (HCHO) has become a hot topic, and completely catalytic oxidation at room temperature has been identified as one of the efficient routes for solving this problem. Recently, it has been reported that zeolite-supported Pt catalysts are active for HCHO oxidation at low temperatures, but they are still unable to completely oxidize HCHO at room temperature. To enhance the activity, it has been suggested to increase the Pt dispersion and acidic density in the zeolite-supported Pt catalysts. We therefore chose Al-rich Beta as a zeolite support because abundant aluminum species in the zeolite framework are advantageous for increasing acidic density through ion-exchange of protons and for improving Pt metal dispersion through the metal-zeolite interaction by increasing the negative charge of the zeolite framework with positively charged metal ions. As we expected, the Al-rich Beta zeolite supported platinum catalyst is very active, giving complete oxidation of HCHO at room temperature. To the best of our knowledge, this is the first time the complete oxidation of HCHO at room temperature over a zeolite-supported noble metal catalyst has been realized. In addition to its extraordinary activity, this catalyst is also very stable and selective. The strategy of designing zeolite-supported noble metal catalysts might offer an alternative way to develop highly efficient heterogeneous catalysts for the removal of air pollutants. (C) 2017 Published by Elsevier B.V.

The rational design of catalytic materials from the reaction characteristics is expected to be a useful strategy to create highly efficient catalysts. Herein, according to a well-established reaction pathway of epoxide hydration catalyzed a dual-molecular system of Co3+/salen in which a high concentration of active sites is favorable to enhance the activity, we provide an alternative way to prepare a highly efficient heterogeneous catalyst with a high concentration of Co3+/salen from the polymerization of vinyl-functionalized salen monomers followed by the loading of Co3+ species (Co3+/POL-salen). Co3+/POL-salen has a hierarchical porosity and an extraordinary hydrothermal stability. Importantly, catalytic tests in epoxide hydration demonstrate that Co3+/POL-salen affords excellent high activities, which are even better than those of the homogeneous version. This phenomenon is related to the very high concentration of Co3+/salen in the catalyst. In addition, this catalyst can be recycled readily because of its excellent hydrothermal stability.

An efficient catalyst system based on a Pd-metalated porous organic polymer bearing phenanthroline ligands was designed and synthesized. This catalyst was applied to various C–C bond-forming reactions, including the Suzuki, Heck and Sonogashira couplings, and afforded the corresponding products while exhibiting excellent activities and selectivities. More importantly, this catalyst can be readily recycled. These features show that such catalysts have significant potential applications in the future.

Mesoporous EU-1 zeolite (M-EU-1) is rationally synthesized from a starting aluminosilicate gel in the presence of small organic template (hexamethonium bromide, HMBr2) and mesoscale cationic polymer (polydiallyldimethylammonium chloride, PDADMAC). After characterizations of the EU-1 with by XRD, N-2 sorption, SEM, TEM, NMR, and TG techniques, it is shown that the sample has good crystallinity, meso/microporosity, high BET surface area (442 m(2)/g), and large pore volume (0.28 cm(3)/g). Particularly, the mesoporosity in the M-EU-1 could be adjusted by the amount of mesoscale cationic polymer added in the starting gels. Catalytic tests in m-xylene isomerization show that the M-EU-1 is more stable than the conventional EU-1 synthesized in the absence of the mesoscale template. (C) 2016 Elsevier Inc. All rights reserved.