Abstract The thermoresponsive behavior of Pluronic F127 (PF127) triblock copolymer solutions is fundamentally governed by temperature-dependent micellization and complex self-assembly of these micelles. However, a comprehensive understanding of the temperature-dependent kinetics and reversibility of PF127 phase transitions during cyclic heating–cooling remains limited. This study systematically investigates the effect of thermal stimuli on the kinetics of phase transition of Pluronic systems during heating and cooling cycles. We employ Differential Scanning Calorimetry (DSC) measurements to investigate the dependence of the micellization temperature on thermal stimuli, revealing that both the micellization temperature and the peak intensity vary systematically with applied thermal ramp rates. Furthermore, we employ rheological characterization which reveals a sharp sol to soft-solid transition upon heating. Interestingly, we observe a novel multistep transition during the cooling cycle, indicating a more complex reorganization pathway with intermediate metastable states than typically assumed for reversible micellization. We also investigate the effect of thermal cycling on the reversibility and thermal stability of the polymer system. Our findings indicate that the characteristic multistep cooling transition is transient, gradually weakening with successive thermal cycles. We also present a phenomenological model which accurately captures the kinetics and multiple-step transition in viscoelastic parameters. Significantly, the distinct peaks in Small-Angle X-ray Scattering (SAXS) measurements under thermal equilibrated conditions clearly reveal the evolution from a disordered unimers/micelles state at low temperatures to a highly ordered lattice with long-range spatial correlation at elevated temperatures. We also present a comprehensive phase diagram highlighting the critical role of thermal stimuli and pathways in defining the phase behavior of Pluronic system. This work, therefore, offers essential experimental and theoretical insights into the thermally driven self-assembly, transition kinetics, and microstructural evolution of thermoreversible Pluronic solution.
Abstract Dry reforming of methane (DRM) converts two major greenhouse gases, CH4 and CO2, into syngas. The products (CO and H2) can be directly utilized as feedstock for chemical processes such as Fischer–Tropsch synthesis and methanol production. Transition metal-based catalysts stand as the most commonly employed for DRM on account of their low cost and excellent intrinsic activity. Nevertheless, the harsh high-temperature conditions readily trigger the sintering of metals and carbon deposition, resulting in rapid catalyst deactivation. This critical drawback severely restricts the large-scale industrial rollout of DRM. Relying on the synergistic effect of spatial confinement and interfacial electronic modulation, confined catalysts can efficiently suppress metal sintering and side reactions. In comparison, some confined catalysts achieve a CH4 conversion of over 90% at a lower temperature, and some catalysts nearly form no graphitic carbon during a long-term durability test of 120 h. In contrast, unconfined catalysts suffer from continuous activity deterioration. This review systematically summarizes recent research progress on confined catalysts for DRM. It thoroughly analyzes anti-coking mechanisms, design criteria and optimization strategies, and clarifies the intrinsic coupling rules among geometric confinement, interfacial electronic effects and multi-dimensional synergistic confinement mechanisms. A horizontal comparison is also conducted to evaluate the advantages and limitations of four categories of confined structures: carbon-based, zeolite-based, MOF-derived, and composite support catalysts. Forward-looking optimization directions are proposed by integrating advanced techniques. The conclusions obtained from this review can provide theoretical foundations and practical references for the rational development of high-performance confined catalysts and the industrial advancement of DRM.
Abstract The efficient and selective elimination of H2S from natural gas holds considerable practical and scientific importance for gas purification. However, the lack of suitable media that enable high H2S/CO2 selectivity has constrained the resource-oriented utilization of both gases. Herein, we present for the first time the synthesis of a series of carbonyl-functionalized deep eutectic solvents (CFDESs). Systematic gas absorption evaluations demonstrate that these CFDESs enable selective and efficient capture of H2S over CO2 and CH4. It is noteworthy that the CFDES derived from 4-methylcyclohexanone (4M-DMAEE) achieves a remarkable H2S uptake of 1.80 mol/mol (7.34 mol/kg) under conditions of 313.2 K and 1.0 bar, marking one of the highest recorded values to date. Leveraging the specific recognition ability of carbonyl groups toward H2S and CO2, 4M-DMAEE shows outstanding H2S/CO2 separation selectivity, particularly under low partial pressure conditions. Moreover, the H2S/CH4 selectivity reaches 519–858 under conditions of 313.2 K and 1.0 bar, outperforming most reported materials. Mechanistic investigations combining NMR, FT-IR, and theoretical calculations reveal a cascade H2S capture process involving nucleophilic addition reactions. Importantly, these CFDESs also feature ultra-low viscosity (<5 mPa·s at 40 °C), favorable mass transfer performance, and excellent cyclic regeneration capability. This work offers a highly selective and energy-efficient separation medium for applications requiring preferential H2S removal and recovery in resource-oriented natural gas upgrading.
Abstract Hydrothermal carbonization (HTC) is a promising pathway to convert wet wastes into energy-rich products. To achieve scalability, further valorization of the aqueous-phase (AP) byproduct is required. For example, HTC AP contains organics that necessitate treatment as well as valuable inorganics for struvite production (MgNH4PO4·6H2O, a slow-release fertilizer). However, direct struvite crystallization from HTC AP suffers from organic and inorganic impurities (specifically, Ca) co-precipitation. To selectively improve the quality of struvite precipitate, this study evaluated wet oxidation (WO) pretreatment for organics degradation before crystallization. Two experimental approaches were evaluated: (1) direct crystallization from HTC AP and (2) crystallization from WO-treated HTC AP (WO AP). The second approach was selected to aim at improved struvite product quality by mitigation of C-organics and other inorganic co-precipitation. HTC was conducted at 190 °C for 30 min with a biomass-to-water ratio of 1:10, while WO was performed at 200 °C and 30 min under 650 psi of O2. Crystallization experiments were performed at pH 9 with mixing at 200 rpm. Phosphorus recovery from HTC AP reached ∼90%, with ∼40% magnesium recovery, whereas WO AP achieved >90% recovery of both phosphorus and magnesium. XRD analysis showed the HTC AP precipitate consists of ∼88% struvite and ∼12% sodium- and carbonate-substituted hydroxyapatite crystalline phases, while the WO AP precipitate was predominantly a struvite crystalline phase. Further, elemental analysis revealed ∼5 wt % carbon and significant inorganic impurities (Ca, Na, and K) in HTC AP precipitates, compared to only ∼1 wt % carbon and minimal impurities in WO AP precipitates. Chemical and functional group characterization further confirmed that WO pretreatment effectively mitigated organic and inorganic co-precipitation, resulting in a higher-purity struvite product.
Abstract Traditional PET methanolysis often suffers from high solvent consumption and complicated downstream purification, particularly when processing colored or contaminated polyester waste. Herein, we report a continuous-flow vapor-phase methanolysis approach using a fixed-bed reactor combined with catalyst-pretreated PET for the depolymerization of waste polyester materials. In this process, methanol vapor continuously passes through the reactor and transports volatile depolymerization products out of the reaction zone during the reaction. Under optimized conditions, the system achieved up to 90% dimethyl terephthalate (DMT) yield, while the condensed products exhibited a combined DMT/MHET purity of approximately 99%. In addition, colored PET feedstocks underwent effective in-situ decolorization during vapor-phase methanolysis, with decolorization efficiencies exceeding 90%. ICP analysis further demonstrated substantially reduced metal contamination in the recovered products compared to conventional liquid-phase methanolysis. These results suggest that continuous vapor-phase methanolysis enables simultaneous PET depolymerization and partial purification within a single-process configuration, providing experimental insights into the treatment and upgrading of colored and contaminated polyester wastes.
Abstract Seaweed-based biostimulants have emerged as promising sustainable agricultural inputs due to their potential to enhance crop productivity, improve nutrient use efficiency, and increase tolerance to abiotic stresses, thereby reducing dependence on synthetic fertilizers. However, the environmental performance of their production systems remains insufficiently quantified. This study presents a cradle-to-gate life cycle assessment (LCA) of a formulated seaweed-based biostimulant derived from Kappaphycus alvarezii, based on representation of a real-world industrial-scale production system in India. Environmental impacts were evaluated across cultivation, biomass transport, sap extraction, and packaging stages using the ReCiPe 2016 midpoint method, with a functional unit of 1 L of packaged commercial seaweed biostimulant at the factory gate. Results indicate that the baseline raft-cultivation system, climate change impact was 0.123 kg CO2-eq per L of packaged commercial biostimulant. Packaging accounts for approximately 74% of cradle-to-gate climate change impacts, primarily due to plastic material production, while extraction contributes ∼21%, largely driven by electricity consumption (>92% within the stage). In contrast, cultivation contributes less than 5% of total cradle-to-gate impacts, with wild harvest having higher impact across most categories compared to raft-based methods. Within raft-based cultivation, polypropylene ropes (53.4%) and HDPE nets (34.6%) account for nearly 88% of impacts, whereas diesel use dominates wild harvesting (∼86.4%). Also, sensitivity analysis shows that increasing transport distance from 50 km to 300 km can increase total climate change impacts by ∼45. An additional multimodal transport scenario (road–sea–road), representing potential international biomass sourcing, resulted in higher transport-related impacts but did not alter the identification of packaging and extraction as the dominant environmental hotspots. Packaging sensitivity analysis indicates that replacing 50% of virgin HDPE with recycled material reduces overall climate change impacts by ∼18.40%. An exploratory baseline substitution scenario, based on nutrient-equivalent offsets of potassium and phosphorus using a system expansion approach, indicates that partial substitution of conventional fertilizers can reduce climate change impacts by approximately 17%. This represents a conservative estimate because it excludes additional field-validated biostimulant effects, such as improved nutrient-use efficiency and crop productivity, which may provide further environmental benefits.
Abstract Na4Fe3(PO4)2P2O7 (NFPP) is regarded as a highly promising cathode material for sodium-ion batteries (SIBs) in energy storage systems. In particular, the low cost and environmental friendliness of NFPP render it especially suitable for large-scale commercialization. Nevertheless, the inherently low ionic/electronic conductivity of NFPP severely impedes its practical deployment in SIBs. Herein, employing a bulk-phase regulation strategy through elemental doping, we prepared Ti-doped Na4Fe3–xTix(PO4)2P2O7/C cathode materials using iron phosphate as both the iron and phosphorus source via a low-cost solid-state method, aiming to further reduce cost and enhance overall material performance. The results demonstrate that moderate Ti4+ doping shortens the average Fe–O bond length, reinforces the structural stability of the crystalline framework, and effectively improves Na+ diffusion kinetics. Among the compositions investigated, the optimized Na4Fe2.94Ti0.06(PO4)2P2O7/C (denoted NFPP-Ti0.06) exhibits the best comprehensive electrochemical properties, delivering outstanding rate capability from 0.2 to 20 C (with a specific capacity of 96.11 mAh g–1 at 20 C, retaining 83.51% of the 0.2 C capacity) and exceptional cycling stability (capacity retention of 99.18% after 400 cycles at 2 C and 82.59% after 3000 cycles at 20 C). Furthermore, a full cell assembled with NFPP-Ti0.06 as the cathode and hard carbon as the anode also exhibited favorable electrochemical performance.
Abstract Simulated moving-bed (SMB) chromatography is a highly efficient novel separation technique. However, the establishment period from start-up in an empty column to cyclic steady state is extremely long. Traditional fixed-parameter start-up modes are not only time-consuming but also result in significant eluent consumption and severe waste of transition products. Current start-up optimization studies often employ staged parameter optimization and rely on preset ideal reference trajectories, neglecting separation performance under steady-state conditions. Therefore, a continuous-time-scale adaptive startup optimization control strategy is proposed. First, the optimal steady-state operating parameters under the current equipment conditions are determined using a computational model. Then, a continuous-time scaling factor and a Hermitian interpolation method are introduced to achieve parameter smoothing and scaling of the optimization time. Finally, a composite objective function is constructed and solved by utilizing a two-layer collaborative optimization architecture. Comparative experiments demonstrate that this strategy significantly reduces start-up time and eluent consumption: it requires only 9.56 h to reach steady state, achieving a 57.3% reduction compared to the 22.42 h required by the traditional fixed-parameter strategy. Furthermore, eluent consumption during the start-up period is drastically decreased from 56 mL in the traditional strategy to just 16 mL. Simultaneously, under the strict premise that the product purity is greater than 99%, the proposed strategy increases the final steady-state productivity by 12.8% compared to the traditional approach. This novel strategy successfully achieves the dual objectives of shortening the start-up time and securing superior separation performance, thereby greatly enhancing overall economic efficiency.
Abstract A copper–zinc–alumina catalyst doped with activated carbon (CZA-0.1AC) is facilely fabricated via the physical mixing method. Mechanistic studies indicate that the intimate carbon–copper contact promotes hydrogen spillover, which suppresses Cu particle aggregation, stabilizes the active Cu valence state, and accelerates intermediate hydrogenation. Benefiting from these multiple positive factors, a record-breaking methanol space-time yield (STY) of 1169 g·kgCZA–1·h–1 is achieved at a gas hourly space velocity of 36,000 mL·gcat–1·h–1. This work provides a facile and reliable strategy to boost the methanol synthesis performance of the copper–zinc–alumina catalyst in CO2 hydrogenation, which is promising to spread into industrial application due to its low cost and ease of preparation.
Abstract Defect engineering of metal-oxide interfaces offers a powerful approach for regulating catalytic hydrogenation, yet its role in the deep hydrogenation of polycyclic aromatic hydrocarbons remains elusive. Herein, we synthesize a series of two-dimensional WOx nanosheets with tunable oxygen vacancy concentrations through a glucose-assisted hydrothermal strategy and construct defect-engineered Pt/D1-WOx catalysts for PAHs hydrogenation. The Ov-rich Pt/D1-WOx catalyst exhibits remarkably enhanced deep hydrogenation performance toward decalin formation compared with defect-free Pt/WO3, achieving a nearly 2.5-fold increase in TOFNA (162.7 gNA gPt–1 h–1). Experimental measurements and theoretical calculations reveal that Ov fundamentally reconstructs the Pt-WOx interfacial microenvironment by strengthening electronic metal-support interactions and stabilizing interfacial Ptδ+–O–W5+ configurations. Meanwhile, Ov adjacent to Pt functions as a hydrogen reservoirs that facilitate hydrogen spillover and maintain high local hydrogen chemical potential around interfacial active sites, which is critical for continuous aromatic ring hydrogenation. The cooperative interplay among interfacial electronic modulation, hydrogen spillover, and substrate activation establishes a hydrogen-enriched catalytic interface for efficient PAHs deep hydrogenation. These findings provide mechanistic insights into defect-regulated metal-oxide interfacial catalysis in aromatic hydrogenation.
Abstract Thermal pyrolysis of isobutyric anhydride (IBAN) to dimethylketene (DMK) requires a rapid and uniform heat supply at high temperature and short residence time. A three-dimensional CFD model coupling flow, heat transfer, and reaction compared a circular tube (CT), twisted elliptical tubes (TETs), and sinusoidally corrugated tubes (SCTs) at identical length and hydraulic diameter. A larger TET aspect ratio or smaller twist pitch improved conversion and yield with moderate pressure-drop penalties. A larger SCT amplitude gave greater yield gains but higher hydraulic costs. At t = 0.8 s, a representative SCT (T = 50 mm, A = 4 mm) raised the DMK yield from 41.57% for the CT to 60.35% at 98.78% selectivity. At comparable yields, TETs required a lower pressure drop than SCTs. TETs sustain inter-section exchange through noncircularity and twisting, whereas SCTs renew near-wall fluid through periodic contraction and expansion. SCTs suit yield-prioritized designs; TETs suit designs that balance enhancement and hydraulic cost.
Abstract Converting waste PET into porous carbon materials for CO2 capture is a promising strategy to achieve waste valorization and carbon neutrality, yet existing methods still suffer from limited structural control, incomplete carbonization, and unclear structural evolution mechanisms. Herein, a facile molten salt-assisted carbonization strategy was developed to fabricate carbon nanosheets (CNS) from waste PET. The effects of molten salt type, ratio, and carbonization temperature on the morphology, pore structure, and surface chemistry of the as-prepared CNS were systematically investigated. The results show that the optimal sample exhibits an ultrathin 2D nanosheet structure with a high surface area of 1825 m2·g–1. This sample exhibited a high CO2 adsorption capacity of 3.87 mmol·g–1, outperforming most reported PET-derived porous carbon materials. Based on systematic characterizations, the intrinsic regulation mechanism of molten salt on the structural evolution of PET-derived carbon was revealed. This work provides a facile and sustainable route for the high-value utilization of waste PET plastic and also offers theoretical support for the design of high-performance CO2 adsorbents.
A novel laminar jet apparatus (LJA) was constructed for precise gas-liquid mass transfer measurements up to 12 bar, significantly extending the technique's operating window. It was applied to carbon dioxide + 1-butanol between 283 K and 333 K. Corresponding measurements were performed using pulsed field gradient NMR spectroscopy (PFG-NMR), which does not involve interfacial mass transfer. Fick diffusion coefficients from LJA and self-diffusion coefficients from PFG-NMR were compared in the limit of infinite dilution, where both must coincide. Both methods show consistent trends, but LJA data are systematically lower. Experimental errors cannot explain the deviations. We therefore hypothesize an additional gas-liquid interfacial mass transfer resistance. PCP-SAFT combined with density gradient theory predicts high CO_2 enrichment at the interface, and the deviations correlate with this enrichment. Whether such an interfacial resistance exists and is caused by enrichment remains to be established in future studies.
Abstract Hydrogen production via catalytic steam reforming of high-carbon hydrocarbons, with low cost, strong adaptability, and easy industrialization, is one of the core technologies for addressing the hydrogen supply bottleneck of fuel cells. However, traditional synthesis methods usually lead to an uncontrollable chemical state of active metals, resulting in poor catalytic activity, low hydrogen selectivity, and rapid deactivation of catalysts. Herein, in situ liquid-phase reduction combined with an adsorption-impregnation method under mild conditions was developed to achieve the controllable regulation of Ni nanoparticle size, dispersion, and valence ratio in Ni/MgAl2O4 catalysts. The results showed that the NMA-160-2 catalyst with Ni nanoparticles that were reduced at 160 °C for 2 h exhibited excellent activity and stability (800 °C, WHSV = 202.3 h–1), which possessed the highest H2 selectivity (71.8%) and maintained the full conversion of methylcyclohexane for 22 h, with the carbon generation rate of 1.6 mg·gCat–1·h–1. It was attributed to highly dispersed and small-sized Ni nanoparticles with a high proportion of Ni0 obtained under this reduction condition, which favored the adsorption and activation of methylcyclohexane and mitigated carbon deposition on the surface of active sites. This work provides a valuable addition to the controllable preparation of high-performance reforming catalysts and the development of fuel cells.
Abstract The particle size of ZIFs has a significant effect on the CO2 separation performance of mixed matrix membranes (MMMs). Herein, an imidazole-mediated protonation strategy was developed to regulate the particle size of ZIF(Cu), achieving tunable sizes spanning more than one order of magnitude (37 nm, 400 nm, and 18 μm). Subsequently, Pebax-based MMMs were fabricated, and the relationship between ZIF particle size and interfacial properties, as well as the effects of particle size and residual imidazole on the CO2 separation performance of MMMs, was systematically investigated. The incorporation of ZIF(Cu) establishes efficient CO2 transport pathways within MMMs, enabling the MMMs containing 5 wt % ZIF (400 nm) particles to achieve a CO2 permeability of 170.7 Barrer and a CO2/N2 separation factor of 54.86 under humid conditions, corresponding to 90.27% and 32.75% improvements over Pebax, respectively. This strategy provides a new approach for controlling ZIF particle size and optimizing MMMs performance.
Abstract Regeneration of oxygen carriers under realistic biomass-derived conditions is constrained by a coupled tradeoff among carbon elimination, lattice oxygen replenishment, and structural preservation. Here, NiFe2O4@SBA-15 was used to investigate regeneration under realistic microalgae-derived conditions and to develop a staged CO2–air regeneration strategy. Compared with the benchmark H2 redox cycle, the regeneration efficiency decreased from approximately 75% to 55% after real microalgae reforming. Among single-atmosphere cases, CO2 delivered the best overall regeneration performance because it promoted carbon removal while suppressing sintering and retaining the mesostructure. A staged CO2–air regeneration strategy further increased regeneration efficiency to about 70%. Multiscale characterizations, especially Mössbauer spectroscopy, showed that CO2 step mainly induced carbon removal and partial Fe reoxidation, whereas the subsequent air step near-complete lattice oxygen replenishment and NiFe2O4 spinel reconstruction. These results demonstrate that temporally separating decarbonization from deep reoxidation is an effective regeneration design principle for redox oxygen carriers.
Abstract Conventional H4PMo11VO40 (HPAV) catalysts for the selective oxidation of methacrolein (MAL) to methacrylic acid (MAA) are limited by insufficient active-site accessibility and poor mass transport. Herein, hollow porous core–shell UF-CsPAV catalysts were prepared using SiO2 microspheres, PEO–PS copolymer, and urea-formaldehyde (UF) resin as a dual-template/organic precursor system. The optimized catalyst exhibited a specific surface area of 438.0 m2· g–1 and well-developed mesoporous channels. During calcination, NH4+ species generated from the UF resin regulated the heteropolyacid environment, increasing acidity, the V4+/V5+ ratio, and terminal oxygen species. At 335 °C and a space velocity of 1020 h–1, the catalyst prepared with 1 μm SiO2 microspheres and 50 wt % CsPAV achieved 88.1% MAL conversion, 91.2% MAA selectivity, and MAA space-time yield (STY) of 1.54 mmol·cm–3·h–1 over 100 h. This work demonstrates an integrated strategy for coupling porous-architecture control with acid-redox regulation in MAL oxidation.
Abstract To contribute to alleviating the depletion of fossil fuel resources and address environmental issues, renewable biomass is being studied in depth for the synthesis of valuable petroleum derivatives. The direct transformation of abundant glucose resources into 2,5-diformylfuran (DFF) is a promising route for producing an alternative candidate on an industrial scale. In this work, we developed a practical approach for preparing various molybdate-based acidic ionic liquid systems for the “one-pot, one-step” production of DFF from glucose, yielding approximately 40% in an acceptable time frame of 3 h through an approachable procedure. The results indicated the high catalytic performance of multifunctional ionic liquid catalysts bearing Lewis acid, Brönsted acid, and oxidation sites to promote DFF production. Therefore, the findings of this work highlight the potential application of molybdate-based acidic ionic liquids as a sustainable strategy for synthesizing high-value chemicals on a large scale.
Abstract In recent years, the significance of decarbonizing petroleum refineries has been increasingly recognized, yet existing studies on refinery planning typically focus on individual decarbonization options, leaving refinery-wide low-carbon transition pathways insufficiently explored. This paper proposes a novel integrated planning framework for the low-carbon transition of refineries, in which electrification features renewable power integration, green hydrogen production, and electrified heat generation, while biomass and waste plastics are introduced into the refinery material network as alternative feedstocks. The framework captures the interactions between electrified energy supply and alternative feedstock transition within a unified planning model. To hedge against renewable-generation and market-price uncertainties, the planning problem is then formulated as a two-stage stochastic programming model that separates here-and-now investment decisions from wait-and-see operational decisions. Given the computational intractability associated with a large number of scenarios, we develop a novel decision-focused scenario reduction algorithm that identifies decision-relevant scenarios using cross-evaluated recourse costs and constructs scenario distances based on a risk-aware candidate set. We further establish a theoretical bound that characterizes the approximation error introduced by the proposed decision-focused scenario reduction. In a refinery planning case study, the proposed framework reduces carbon emissions by 6.21% and crude oil consumption by 2.67%, while improving economic performance by 9.32% relative to the benchmark configurations. Moreover, the proposed solution algorithm outperforms state-of-the-art methods by up to an order of magnitude in approximation error, thus demonstrating its strong effectiveness in preserving solution quality while significantly improving tractability.
Abstract Hydrogenated bisphenol A (H12BPA) serves as a high-performance alternative to bisphenol A (BPA) in polymer and electronic materials. However, the hydrogenation of BPA faces significant kinetic barriers, requiring high Ru loading and resulting in low selectivity and high cost. Herein, a continuous microreactor was employed to enhance multiphase mass transfer and improve reaction efficiency. After optimizing the reaction parameters, a 2.0 wt % Ru/C catalyst achieved 100% BPA conversion and 99.1% H12BPA selectivity at 130 °C and 3.0 MPa, maintaining stable performance over 700 h continuous operation. A kinetic network model well matched the experimental data, and the hydrogenation of the intermediate H6BPA to H12BPA is the rate-determining step. This work provides a scalable route for BPA hydrogenation and reliable kinetic parameters for continuous-flow process design.
