A series of composites CxPMo4@MIL-100(Fe) (x = 4, 8, 12, and 16) were synthesized via one-pot solvothermal method, characterized by various techniques, and employed as catalyst for extraction oxidation desulfurization of multicomponent simulated fuel. Among them, C8PMo4@MIL-100(Fe) exhibited optimal catalytic activity, achieving 99.8% total desulfurization efficiency within 60 min under the optimal conditions. In addition, the desulfurization efficiency decreased in the sequence DBT > 4-MDBT > 4,6-DMDBT > BT, which was attributed to the interplay between steric hindrance and electron density of the sulfide molecules. Furthermore, C8PMo4@MIL-100(Fe) exhibited excellent reusability, maintaining an efficiency of over 92% after six consecutive cycles. These findings emphasize the crucial role of adjusting the interaction between polyoxomolybdenum and metal-organic frameworks to achieve efficient and sustainable fuel desulfurization, and provide a theoretical basis for the rational design of high-performance heterogeneous catalysts.

In recent years, the escalating global demand for clean energy has underscored the urgency of developing highefficiency fuel desulfurization technologies. This study reports the facile synthesis of a molded fiber-supported composite catalyst, POM@UiO-66-NH2@CF (PUNC), via impregnation, integrating polyoxometalates (POMs) with amino-functionalized metal-organic frameworks (MOFs) on cellulose fibers (CF). The catalyst delivers exceptional performance in ultra-deep oxidative desulfurization (ODS), enabled by systematic optimization of reaction parameters using response surface methodology (RSM) with a Box-Behnken design (BBD). Through RSM optimization and adjustment, the actual desulfurization conditions were determined as 66 degrees C, O/S = 7, 7 mL DMF, and 2 catalyst pieces and PUNC achieved a validated 99.26 % desulfurization efficiency for dibenzothiophene (DBT) in model fuels, demonstrating close agreement with theoretical predictions. Kinetic analysis revealed the ODS reaction conformed to a pseudo-first-order kinetic model with a low activation energy of 2.45 kJ/mol, while EPR spectroscopy confirmed center dot O-2(-) radicals as the dominant reactive species, highlighting a POMmediated radical oxidation pathway. PUNC exhibited robust reusability, maintaining >95 % efficiency over 5 consecutive cycles. The catalyst's performance is attributed to the synergistic architecture of MOF-fiber supports, where 3-chloropropyltrimethoxysilane (CPTMS) enables covalent bonding of UiO-66-NH2 to CF, creating aminerich sites for electrostatic POM immobilization and enhanced stability. This work showcases the synergy between structural design and RSM-driven optimization, offering innovative insights for developing high-efficiency, environmentally benign molded catalysts for ultra-deep ODS and related oxidative processes.

In this study, a composite PW11Cr@MOF-525 was successfully synthesized by encapsulating chromium-substituted phosphotungstate (PW11Cr) into the zirconium-based metal-organic framework MOF-525 via a simple impregnation method. The composite was characterized by XRD, FT-IR, BET, TGA, XPS and SEM, confirming the uniform dispersion of PW11Cr within MOF-525's mesoporous channels. As a heterogeneous catalyst for extractive oxidative desulfurization (EODS), PW11Cr@MOF-525 exhibited good performance under mild conditions, achieving a total desulfurization efficiency of 94.5 % for multi-component fuel containing four refractory organic sulfides. The encapsulation of PW11Cr in MOF-525 effectively stabilized the active species, ensuring minimal leaching and high recyclability (maintaining >80 % efficiency over 9 cycles). This work exemplifies a synergistic catalysis theory, where the Lewis acid-base interaction at the PW11Cr-MOF-525 interface not only ensures stability but also modulates electronic structure to enhance catalytic kinetics. This strategy combines the catalytic activity of POMs with the mass transport advantages of MOFs, providing a highly promising strategy for deep desulfurization of fuel.

The simultaneous removal of emulsified water and refractory sulfur compounds from crude oil remains a critical industrial challenge due to mass transfer limitations and environmental burdens. Conventional technologies require sequential demulsification and desulfurization steps, resulting in high energy consumption and secondary pollution risks. In this work, we propose a "waste-to-wealth" strategy by synthesizing a bifunctional biohybrid catalyst (Card-PIL@POM) using agricultural waste-derived cashew nut shell liquid (CNSL) and polyoxometalates (POMs). The CNSL-based poly(ionic liquid) matrix effectively anchors POM active species, enabling synergistic demulsification and catalytic oxidation in a single system. Under optimized mild conditions (60 degrees C, O/S molar ratio = 6, catalyst dosage = 1.25 mL), the optimal catalyst (Card-PIL@POM-2, POM/Card-PIL mass ratio = 1:0.10) demonstrates exceptional performance: 99.82% removal of dibenzothiophene from model oil and 94.29% desulfurization efficiency for real emulsified high-sulfur crude oil (1.295 wt% S), along with complete phase separation (100% water removal) within 200 min. Kinetic analysis reveals a low apparent activation energy (32.26 kJ/mol), and the catalyst maintains high stability over seven consecutive recycling tests with no detectable active species leaching. Mechanistic studies identify a superoxide radical (O2 center dot-)-mediated reaction pathway, facilitated by the redox-active Mo/W centers. Life cycle assessment highlights the environmental advantages of this bio-based catalyst, showing 32% reduction in global warming potential and 47% lower human toxicity potential compared to petroleum-derived analogues. This work presents an integrated, energy-efficient, and sustainable catalytic system for the simultaneous demulsification and deep desulfurization of emulsified high-sulfur oils, advancing both circular economy and green chemistry objectives.

A copper(II) compound was synthesized in a green solvent from a sulfur-containing tripodal carboxylic acid ligand. Structural analysis shows that the compound self-assembles into one-dimensional chains, with each copper node forming a classic double-wheel paddle-wheel structure. The synthesized compound was then characterized by PXRD, FTIR, and Uv-vis to confirm its composition and structural integrity. The electrochemical properties were investigated using a three-electrode system. The cyclic voltammograms showed a pair of distinct redox waves, the reversibility of which was further verified by linear sweep measurements. The findings highlight the promising electrochemical activity of the synthesized compound.

The synthesis pathway critically dictates the physicochemical properties and ultimate performance of heterogeneous catalysts. In this study, a peroxophosphotungstate (PW4) was encapsulated into zirconium-based metal - organic framework (MOF-808) via two distinct strategies: post-synthetic impregnation and one-pot solvothermal synthesis. Although both composites exhibited high initial activity in the extraction and oxidation desulfurization of model diesel, PW4@MOF-808-S demonstrated exceptional stability, with only a 5.1% efficiency loss after ten cycles. This superior performance is attributed to the more stable encapsulation achieved through the in-situ approach. Furthermore, PW4@MOF-808-S achieved 99.9% desulfurization under optimized mild conditions (70 degrees C, O/S = 3). This work underscores that the choice of synthesis strategy is paramount for engineering optimal activity and long-term stability in POM@MOF composites.

The development of high-efficiency catalysts is pivotal for the deep desulfurization of fuels, an environmentally benign process operating under mild conditions. Herein, a series of W-based heterojunction catalysts were fabricated through in-situ pyrolysis of PW12-encapsulated NH2-UiO-66 (PW12@NH2-UiO-66) at temperatures ranging from 700 to 1000 degrees C under nitrogen. Characterization results show that the pyrolysis temperature plays a crucial role in the evolution of the heterojunction structure, including the crystal phases (WO3 and WCx), microstructure, and the valence state of tungsten. The catalyst (C-PW12@NH2-UiO-66-900) pyrolyzed at 900 degrees C exhibited outstanding performance, achieving a 99.4 % DBT removal rate within 40 min under optimized conditions. This excellent activity is attributed to its optimized porous structure, which facilitates mass transfer, and the presence of the highest concentration of low-valent W4 + species, which synergistically enhance the catalytic activity. Additionally, this catalyst demonstrates excellent stability and recyclability, maintaining over 90 % desulfurization efficiency after 10 consecutive cycles. Kinetic studies confirmed that the reaction follows a pseudo-first-order model, with an activation energy of 60.7 kJ/mol. This work elucidates the structure-activity relationship of MOF-derived heterojunction catalysts and provides a feasible strategy for designing advanced catalysts for ultra-deep desulfurization.

With growing demands for high-quality liquid fuels, sulfur removal has become critical for the refining industry. POM@MOF composites, which combine the advantages of polyoxometalate (POM) and metal-organic framework (MOF), show great potential in sulfide oxidation. This study focuses on the synthesis and characterization of (TBA)3PMoVI4 @MOF-808(Zr) and (TBA)3PMoV4@MOF-808(Zr), and their applications in extraction oxidation desulfurization (EODS). These two composites with different valence Mo were synthesized via impregnation and solvothermal methods, respectively. XPS analysis confirmed the reduction of (TBA)3PMoVI4 to (TBA)3PMoV4 during the synthesis process. EODS tests showed that (TBA)3PMoV4@MOF-808(Zr) possesses better catalytic activity due to its uniform active-component dispersion and pentavalent molybdenum. The effects of H2O2 dosage, catalyst amount, and reaction temperature on DBT removal rate were investigated, and the oxidation kinetics of DBT was studied. A possible EODS mechanism was proposed, involving hydrogen-peroxide activation, DBT oxidation, and catalyst regeneration. The catalyst (TBA)3PMoV4@MOF-808(Zr) also showed good reusability and structural stability, holding great potential for practical desulfurization applications. Environmental implication: The synthesis of POM@MOF composites via impregnation and solvothermal methods for fuel desulfurization reduces sulfur-containing pollutants emissions. The efficient (TBA)3PMoV4@MOF-808(Zr) catalyst reduces sulfides in fuel under mild conditions, and its reusability and stability minimize waste, contributing to sustainable environmental protection.

As a typical representative of antibiotic contaminants, tetracycline (TC) remains persistent in surface water and wastewater. Coordination polymers have been confirmed to represent a highly efficient strategy for pollutant removal. In this study, a novel U(VI)-containing polymer, [UO2(Htci)]·7.5H2O, was obtained hydrothermally using uranyl nitrate hexahydrate and tris(2-carboxyethyl) isocyanurate (H3tci). Structural characterization by single-crystal X-ray diffraction indicated a 2D layered crystalline architecture. The compound is interconnected by 3-connected Htci2− anions to afford a characteristic (6, 3) honeycomb topological network. The ligand displayed a special cis-cis-trans conformation, and all carboxylic acid groups were bis-chelating. In addition, the compound was characterized by elemental analysis, FT-IR spectroscopy, powder X-ray diffraction (PXRD), thermal analysis, and photoluminescence spectroscopy. The photodegradation efficiency of TC reached 93.2% after 120 min under irradiation with UV light. At the same time, metal ion sensing of the compound revealed selectivity in recognition of Fe3+, with a detection limit of 0.77 mg·L−1 being achieved.

The global demand for sustainable and cleaner energy sources has driven more research on advanced desulfurization technologies from fossil fuels, in which oxidative deep desulfurization has become a hotspot. In this paper, the nucleation-controlled method was used to realize the uniform growth of porous amino metal-organic framework (MOF) on green-friendly cotton fibers (CF), and the pore structure and amino functional groups on MOF were beneficial to firmly anchor of P-Mo-W polyoxometalate (POM) active species. Thus, a kind of new supported P-Mo-W POM composite catalyst (POM@MIL-101@CF) has been obtained and exhibited excellent oxidative desulfurization performance for fuels. Under the optimal reaction conditions: T = 60 degrees C, O/S = 7, two pieces of catalyst, the ODS efficiency of 0.5-POM@MIL-101@CF for DBT could reach 99.57%, with slight changes after more than 5 reuse times. Meanwhile, EPR experiments proved that O-2(-) and OH radicals were both the main reactive substances, which promoted the remarkable catalytic desulfurization performance of POM@MIL-101@CF. Therefore, this kind of supported POM catalyst is simple to prepare and green-friendly in raw materials, as well as the strong binding between POM and CF with the bridging effects of MIL-101 makes it better adapt to the needs of actual industrial production and has a broad application prospect in practical desulfurization applications.

Lignin, a major component in renewable plant biomass, serves as a potential source of high-value aromatic chemicals. However, efficiently decomposing lignin while maintaining its aromaticity for fossil fuel substitution remains a significant challenge. This study synthesized a [VimAm]Br@POM@AC catalyst, composed of a Keggin-type polyoxometalate (POM) modified by ionic liquid ([VimAm]Br) and supported on activated carbon (AC). The response-surface methodology was applied to explore the catalytic performance of this catalyst in the oxidative depolymerization of lignin β-O-4 model compounds. Under the reaction conditions of 160 °C, 3 mL H2O2, and 0.4 g catalyst within 8 h, the conversion rate of lignin model compounds reached 83.01 %. The reaction generated diverse aromatic products, with the selectivity of methyl mandelate and methyl benzoate reaching 27.70 % and 59.02 %, respectively. Mechanistic studies revealed that the [VimAm]Br@POM@AC catalyst selectively cleaves CO bonds in β-O-4 dimers, facilitating the formation of aromatic compounds. Moreover, FT-IR spectroscopy and SEM analysis confirmed the good stability of the recovered catalyst. This work achieves efficient directional conversion of lignin model compounds through the design of a multilevel-structured catalyst, precise optimization of reaction conditions, and innovative mechanistic interpretation. It offers a novel strategy with both academic significance and application potential for the high-value utilization of biomass resources.

Three-dimensionally ordered macro-microporous 3DOM-ZIF-8-based peroxophosphotungstate (DIL-PW4) is constructed to break the limitation of micropores inherent in traditional supported catalysts. The presence of ordered macropores expose more active sites and significantly enhance mass diffusion, thereby boosting catalytic activity, especially in reactions involving larger molecules. The prepared composite DIL-PW4@3DOM-ZIF-8 is verified by various characterization techniques and used as a catalyst for the extraction oxidation desulfurization of multi-component simulated fuel. The results showed that heterogeneous catalyst DIL-PW4@3DOM-ZIF-8 has a remarkable catalytic effect, with 97.03% total sulfides removal in 120 min. In addition, the stability and reusability of the catalyst DIL-PW4@3DOM-ZIF-8 are evaluated as important parameters for industrial applications. In addition, a possible mechanism based on experimental studies are proposed.

Supercapacitors are promising energy storage devices owing to their exceptional power density, rapid charge/discharge capabilities, and outstanding cycling stability. Nevertheless, their limited capacitance restricts practical applications. We developed CoMn-MOF nanorod electrodes via an in-situ etching strategy using metal-organic frameworks (MOFs) as templates. The unique in-situ modification approach effectively constructs nanorod structures with substantially enlarged specific surface area, which significantly enhances the electrode-electrolyte interaction and charge transfer efficiency. The optimized CoMn-MOF-15 electrode demonstrates remarkable performance, delivering a high specific capacity of 189.3 C g−1 at 1 A g−1, while the energy density of the constructed asymmetric supercapacitor with activated carbon (CoMn-MOF-15//AC) achieves up to 124.1 Wh kg− 1 at a power density of 584.0 W kg− 1. In addition, the constructed material maintain excellent cycling stability with 76.38

Inspired by the fact that human nose cilia can effectively contact with particles to prevent their entry into our body, this kind novel biomimetic structures are designed and synthesized to enable the loading efficiency between the polyoxometalate catalytic species (POMs) and the carrier, thereby improving their loading rate and promoting their catalytic performance. The mullite whiskers-uniformed cordierite (CMW) is used as a carrier to support POMs, in which mullite whiskers regarding as the cilia in our nose, this kind catalyst could not only overcome the shortcomings of simple POMs with low specific surface and easy to self-agglomerate, but also could greatly increase their contact probability with the carrier. At the same time, the advantage of the cordierite block structure also greatly conducive to their actual application value on the reusing operation. A series of Keggin-type POM-loaded bulk materials, POM@CMW, [VimAm]Br@POM@CMW, [DVim]Br@POM@CMW, have been developed with various ionic liquid-based POMs (ionic liquid = ILs, chosen these two kinds of [VimAm]Br and [DVim]Br) to a comparative study. The oxidative desulfurization reaction (ODS) for fuels was performed using the obtained materials as catalysts and H2O2 as oxidant, without the additional extractants for the existing of ILs in catalyst. Through experimental evaluations, [DVim]Br@POM@CMW was found the excellent efficiency on the Sulfur removal, with an DBT removal of 96.34 % at 70 degrees C for 120 min. According to the FT-IR and SEM results after the reaction, the catalyst could retain their original structure and the dibenzothiophene (DBT) removal could still be maintained above 95 % after 7 reuses. Furthermore, the oxidation reactivity of different substrates was in the following order: DBT > 4,6-dimethyldibenzothiophene (4,6-DMDBT) > thiophene (BT) and the high activity in actual diesel oil could be also exhibited. The enhanced reaction activity, excellent structural stability, and recyclability can be attributed to the abundance of active sites and outstanding mechanical properties provided by cordierite/mullite whiskers as a carrier, indicating their potential in the novel biomimetic-structured POMs-loaded catalysts.

Environmental concerns stemming from sulfur oxides released during liquid fuel combustion have urgently necessitated the development of low-sulfur or sulfur-free fuels. The limitations of hydrodesulfurization have prompted the exploration of other new technologies. This study innovatively focuses on extraction oxidation desulfurization, employing iron-substituted phosphotungstate PW11Fe encapsulated in PCN-223 as a heterogeneous catalyst (PW11Fe@PCN-223). This composite material combines the unique properties of PCN-223 and PW11Fe, offering enhanced catalytic activity and recyclability. The synthesized materials were characterized using a variety of techniques, and their catalytic performance was evaluated. Kinetic studies revealed that the removal of the three sulfides (BT, DBT, and 4-MDBT) in the simulated diesel adheres to quasi-first-order kinetics. Notably, the results of electron paramagnetic resonance spectroscopy (EPR) and gas chromatograph-mass spectrometry (GC-MS) confirmed that sulfides were oxidized to corresponding sulfones in the presence of hydroxyl radicals, providing new insights into the reaction mechanism. This research thus presents a novel and effective approach to liquid fuel desulfurization.

The small-module involute internal splines have a compact structure, high surface hardness after carburization, and difficult-to-machine material properties. The adoption of PECM technology has significant technical and economic advantages. However, due to the narrow channels of the part, electrolytic products are easy to accumulate in the gap, and there are differences in the material dissolution rate at different positions of the parts, and resulting in uneven distribution of electrolyte conductivity, thereby affecting the machining accuracy. To improve the discharge efficiency of products in the machining area, the multi-physical field coupling simulation methods were used to compare and analyze the flow field characteristics corresponding to different electrolyte flow forms. The electrolyte flow form and flow field parameters were optimized to improve the flow field stability and flow velocity distribution consistency; To improve its forming accuracy, the cathode was designed based on 3D dynamic forming simulation technology, and experimental verification was carried out. The experimental results show that the machining process is stable, the tooth profile error is less than 0.033 mm, and the tooth alignment error is less than 0.015 mm. It can meet the machining technical requirements of the small-module internal splines for difficult-to-machine materials, and has significant technical and economic value.

After heat treatment, the small-module internal splines have a high surface hardness and the parts are deformed. Precision electrolytic shaping machining has good technical and economic advantages. However, the machining accuracy and surface quality are significantly affected by the flow field. To improve the uniformity of the electrolyte flow field, a design scheme for the bidirectional variable cross-section cathode flow-guiding structure was proposed. Based on the flow field simulation method, the influence of the cathode flow-guiding structure and its key dimensions on the flow field distribution was analyzed, and electrochemical machining experimental research were carried out. The simulation and experimental results show that the bidirectional variable cross-section cathode flow-guiding structure is beneficial for improving the stability of the flow field and the consistency of the velocity distribution; The cathode feed rate is 15 mm·min−1, and the tooth profile error can be controlled within 0.033 mm. When the machining depth is 50 mm, the tooth alignment error is within 0.015 mm, and the surface roughness Ra is less than 1.0 µm. The bidirectional variable cross-section cathode flow-guiding structure can meet the practical requirements of the small-module internal splines machining accuracy and surface quality, and has obvious technical and economic advantages.

Abrasive flow machining (AFM) is increasingly preferred to finish closed complicated flow channels machined by electrical discharge machining (EDM) owing to its high machining accessibility, surface integrity, and efficiency. The machining accuracy of closed complicated flow channels by AFM is dependent on the uniformity of material removal distribution (named as finishing nonuniformity here), but few studies on the finishing nonuniformity have been done so far. Firstly the finishing nonuniformity for EDM machined complicated flow channel by AFM was modeled and analyzed theoretically. Then three blisk with EDM surface roughness of R a 1.5 μm, R a 2.0 μm, and R a 3.0 μm were finished by AFM to R a 0.8 μm, and their finishing nonuniformity was compared. Finally, AFM flow simulation was carried out, and the simulation results were compared with that from the experiments. Theoretical results showed that finishing nonuniformity is resulted from the non-uniform flow field of the abrasive medium, and it increases with increasing EDM surface roughness and decreasing AFM surface roughness. This is verified by the AFM experiments and flow simulations. On this basis, the guideline for parameter optimization in the combined EDM + AFM process was discussed.

In this work, a novel heterogeneous catalyst consisting of peroxophosphotungstate, microporous MOF-808, and mesoporous SBA-15 was synthesized, characterized, and used to remove sulfides from model fuel. The prepared material, PW4@MOF-808@SBA-15, exhibits excellent catalytic activity with a desulfurization efficiency of 99.8% in 60 min for multicomponent simulated fuel, and the desulfurization rate can reach more than 90% after ten consecutive cycles. The excellent catalytic activity and reusability are attributed to the hierarchically porous hybrid material MOF-808@SBA-15, which can effectively encapsulate PW4 and provide a site for the oxidation of sulfides.