The upgrading of underutilized methane in shale gas with anthropogenic CO₂ can produce the value-added syngas via dry reforming. Nickel-based catalysts, due to their efficiency and cost-effectiveness, have received widespread attention. However, Ni-catalyzed dry reforming of methane is usually subjected to sintering or coking-induced instability. To address these issues, a series of Al₂O₃-supported nickel nanoparticle catalysts with uniform sizes are synthesized by varying the calcination temperatures and applied in methane dry reforming (DRM). Ni/Al₂O₃-700 °C catalyst behaves better catalytic performance compared to the other catalysts, which can be attributed to its higher metal dispersion and stronger metal-support interaction. In addition, the abundant moderate-strength basic sites and optimal Al_IV/Al_VI ratio can promote the adsorption and activation of CO₂ and suppress the deep cracking of CH₄ for Ni/Al₂O₃-700 °C catalyst, respectively, causing the enhancement of anti-coking performance. Furthermore, combining CH₄-temperature programmed surface reaction and in situ Fourier transform infrared spectroscopy demonstrates that the presence of CO₂ can promote the activation of CH₄ for Ni/Al₂O₃-700 °C catalyst, which is rate-determining step for DRM system. These findings provide valuable theoretical guidance for the rational design of Ni-based catalysts with enhanced catalytic performance.

Cyclone separators are extensively utilized for the efficient separation of solid particles from fluid flows, where their operational effectiveness is intrinsically linked to the equilibrium between pressure drop and collection efficiency. However, in extreme industrial environments, such as fluidized catalytic cracking processes, severe wall erosion poses a significant challenge that compromises equipment lifespan. The present study aims to identify an optimal trade-off among separation efficiency, energy consumption, and erosion rate through the optimization of geometric ratios in cyclone separators. By adjusting specific key dimensions, erosion can be mitigated, extending the separator’s lifespan in harsh conditions. The relationships between six geometric dimension ratios and inlet gas velocity with respect to performance indicators are systematically investigated using design of experiments and computational fluid dynamics simulations. To develop a robust performance prediction model that accounts for multiple influencing factors, an auto machine learning approach is employed, incorporating ensemble learning strategies and automatic hyperparameter optimization techniques, which demonstrate superior performance compared to traditional artificial neural network methodologies. Furthermore, pareto-optimal solutions for maximizing separation efficiency while minimizing pressure drop and erosion rate are derived using the non-dominated sorting genetic algorithm II, which is well-suited for addressing complex nonlinear optimization problems. The results show that the optimized cyclone separator design enhances separation efficiency from 76.19% to 87.95%, reduces pressure drop from 1698 to 1433 Pa, and decreases the erosion rate from 8.06 × 10^–5 to 7.32 × 10^–5 kg·s^–1, outperforming the conventional Stairmand design.

Ligand modification of Cu catalysts has emerged as a promising strategy to enhance activity and stability in acetylene hydrochlorination. However, the limited availability of primary coordinating heteroatoms hinders precise engineering of the Cu active site microenvironment. Herein, a secondary coordination sphere modulation strategy was developed using various substituted hydrocarbon groups in the ligands. The local microenvironment around the Cu active sites was precisely tuned, leading to the Cu⁺ ratio of freshly prepared catalysts and reactive activity revealing a linear correlation, and the C₂H₂ adsorption energy exhibiting a distinct volcano plot correlation with catalytic activity. Among these catalysts, Cu-MMTB/AC exhibited the highest activity, achieving an acetylene conversion of 88.5% under the reaction conditions (T = 180 °C, gas hourly space velocity (GHSV) (C₂H₂) = 180 h⁻¹, and V(HCl): V(C₂H₂) = 1.2). Moreover, ^1#Cu₃-MMTB₁ exhibits advantages in both intermediate formation and HCl activation processes along the reaction pathway. This strategy offers a new avenue for designing high-performance Cu catalysts and promoting the use of mercury-free industrial catalysts.

To obtain high-performance flame-retardant epoxy resin (EP), diglycidyl ether of (2,5-dihydroxyphenyl) diphenyl phosphine oxide (DPO-HQ-EP) was synthesized. EP/DPO-HQ-EP samples with varying phosphorus contents were prepared by curing a mixture of DPO-HQ-EP and diglycidyl ether of bisphenol A. The incorporation of DPO-HQ-EP significantly enhanced the flame retardancy of EP without compromising its glass transition temperature. The EP/DPO-HQ-EP/0.6 exhibited a limited oxygen index of 31.7% and achieved a V-0 rating in the vertical burning test. In the cone calorimeter test, due to the incorporation of DPO-HQ-EP, the peak of heat release rate and total heat release of EP/DPO-HQ-EP/0.6 decreased by 39.4% and 15.9% compared with the values for pure EP. A detailed investigation of the flame-retardant mechanism revealed that the improved flame retardancy of EP/DPO-HQ-EP samples was attributed to the release of phosphorus-containing free radicals and non-flammable gases in the gas phase, as well as the formation of a continuous and dense char layer in the condensed phase. Moreover, the dielectric constant and dielectric loss factor of EP/DPO-HQ-EP samples were lower than those of EP/0. The water absorptivity and transparency of EP were effectively preserved with the incorporation of DPO-HQ-EP. These findings highlighted the potential of EP/DPO-HQ-EP for industrial applications in an electrical field.

Herein, a one-pot method is proposed to manufacture recyclable polyvinyl alcohol/cellulose nanofibers composites with excellent mechanical and barrier performance through wet co-milling of the 2,2,6,6-tetramethylpiperidine-1-oxyl oxidized bamboo pulp in the polyvinyl alcohol aqueous solution. This strategy achieves ultrafine nano-fibrillation of cellulose pulp into nanofibers and their simultaneous homogenous distribution in the polyvinyl alcohol matrix, as evidenced by the homogenized structural morphology and enhanced interfacial interactions. With increased grinding degree, the cellulose fibers are gradually exfoliated and uniformly distributed in the polyvinyl alcohol matrix. The structure evolution of polyvinyl alcohol/cellulose composites during exfoliation and the structure-properties relationship are systematically analyzed. Consequently, the resultant polyvinyl alcohol/cellulose nanofibers composite films exhibit a ‘reinforced concrete’ structure with improved grain boundary strengthening effect, stress transfer capability and barrier properties. The elastic modulus, tensile strength and toughness of the polyvinyl alcohol/cellulose nanofibers composite films are significantly enhanced by 195.1%, 33.8% and 56.2% compared to those of pure polyvinyl alcohol film, respectively. The greatly reduced oxygen permeability coefficient demonstrates their great potential in food packaging. This research proposes a practical one-pot method for the fabrication and structure regulation of polyvinyl alcohol/cellulose nanofibers composites and provides valuable insights into their structure-property relationships.

Selective oxidation of n-butane to maleic anhydride (MA) is considered an effective approach to realize the utilization of lighter alkanes into useful chemical products. Currently, vanadium phosphorus oxide (VPO) is the most widely used catalyst for the selective oxidation of n-butane to MA owing to its abundant active sites and oxygen species. However, the development of efficient VPO catalysts remains urgent, as the MA yield is limited by the inherent “trade-off” effect between n-butane conversion and MA selectivity. This review systematically summarizes the progress in the rational design and precise regulation of VPO catalysts, with a particular focus on the influence of physicochemical properties on catalytic performance. More importantly, advanced synthesis routes and modification strategies are discussed in detail. These strategies for modulating the geometric and electronic structures of VPO catalysts are highlighted, accompanied by a discussion of the structure-activity relationship. Finally, the challenges of VPO catalysts are discussed, and future research directions are proposed.

The selective oxidation of ethylene glycol to glycolic acid on the Pt₄, Pt₁₃, Pt₃₈, and Pt₅₅ clusters was investigated by using density-functional theory calculations. The calculated results imply that glycolic acid is preferentially generated through the dehydrogenation of ethylene glycol by OH to form HOCH₂CH₂O on the Pt₄, Pt₁₃, and Pt₃₈ surfaces, but that this process occurs directly without OH participation on the Pt₅₅ surface. The observed effect likely arises from the addition of OH, which modulates the electron density in the O atom of ethylene glycol, thereby affecting the cleavage of the O−H bond. Furthermore, the glycolic acid formation on the Pt_n clusters is limited by the β−H elimination of HOCH₂CH₂O to HOCH₂CHO, which exhibits the lowest energy barrier on the Pt₁₃ surface. It is because the d-band center of the Pt₁₃ cluster is closer to the Fermi energy than that of other clusters, which then enhances the electronic density of Pt. This facilitates the adsorption of HOCH₂CH₂O at the Pt sites and the activation of the C−H bond in HOCH₂CH₂O and therefore results in superior catalytic performance. This paper offers theoretical insights into the influence of Pt size on the selective oxidation of ethylene glycol to glycolic acid.

The rapid accumulation of plastic waste poses severe environmental challenges. Cold plasma-driven degradation offers a promising route to convert plastic waste into high-value chemicals. In this study, a single-stage plasma reactor coupling cold plasma (dielectric barrier discharge) with Hβ zeolites was developed for polyethylene degradation under relatively mild conditions, without external thermal input or participation of noble metals. The effects of zeolite pore structure and acidity toward product distribution were investigated, revealing that Hβ-25 exhibited the highest C₁–C₆ yield (76 wt %) and a space-time yield of 103.8 mmol·g_cat^–1·h^–1 compared to other zeolite catalysts during the plasma-catalytic process. Meanwhile, it was revealed that efficient pre-cracking initiated by plasma activation and the optimal structural compatibility between Hβ-zeolite pore channels and primary cracking products were the key factors enabling the selective conversion of polyethylene into C₁–C₆ hydrocarbons. Additionally, metal incorporation significantly enhanced C–H bond cleavage compared to Hβ-25 support. Especially, 10Ni/Hβ-25 exhibited the highest hydrogen yield (7.87 mmol·g_plastic^–1) under plasma-assisted mode, markedly surpassing its yield under thermal-cracking conditions, demonstrating the significant potential of plasma-catalytic degradation for hydrogen production from polyethylene.

5-Hydroxymethylfurfural (5-HMF) is a versatile platform chemical that can be derived from renewable biomass using homogeneous or heterogeneous acid catalysts. However, efficiently separating and purifying 5-HMF from reaction mixtures remains a critical challenge for its high-value conversion from renewable biomass. To address this challenge, various separation methods have been developed, including distillation, adsorption, liquid-liquid extraction, supercritical carbon dioxide extraction, and integrated separation processes. This review summarizes and discusses recent advancements in the separation and purification of 5-HMF from reaction solutions. It evaluates key parameters such as adsorption capacity, separation selectivity, recovery efficiency, and their influencing factors. The liquid-liquid extraction using biphasic solvents has proven to be a simple, cost-effective, and efficient approach. The ionic liquid extraction, deep eutectic solvent extraction, supercritical carbon dioxide extraction, and integrated separation technologies (e.g., liquid-liquid extraction combined with vacuum distillation, distillation integrated with adsorption) are discussed. This review also provides insight into the mechanisms of different separation methods, which may contribute to the development of new processes for the purification of 5-HMF. This review aims to provide a theoretical basis for the future large-scale, efficient, and economic production of high-purity 5-HMF.

Microporous and mesoporous silicalite-1 (S-1) and titanium silicalite-1 (TS-1) zeolite supported molybdenum (Mo) catalysts were synthesized and applied in the transesterification of Jatropha seed oil (JO) to produce biodiesel. Various analytical results have revealed that the MoO₃ species are highly dispersed on their surface without destroying the zeolite framework and pore structure. Compared with the mesoporous 7Mo/mesoporous S-1 and 7Mo/mesoporous TS-1 catalysts, the microporous 7Mo/S-1 and 7Mo/TS-1 catalysts exhibit high Mo species contents and surface acidity, indicating that Mo species can enter the inner surface of mesoporous zeolites. However, the Mo species on the outer surface of catalysts are only activity centers owing to the accessibility between the Mo species and JO. Therefore, compared with the low activity of the S-1 and TS-1 catalysts, the 7Mo/S-1 catalyst exhibited the highest catalytic performance, with a JO conversion of 95.7% and a biodiesel selectivity of 99.9%. Finally, 7Mo/S-1 demonstrated good catalytic stability, regeneration performance and broad substrate versatility, and the fuel properties of the as-synthesized biodiesel conformed to the current international standard. The influence of the pore structure and Mo species on the catalytic activity has been clarified, providing a theoretical and practical foundation for developing efficient heterogeneous catalysts for biodiesel production.