Frontiers of Chemical Science and Engineering最新文献

Plasma-based gas conversion has emerged as a sustainable and promising approach for chemical production, attracting increasing attention in recent years. Significant progress has been achieved in areas such as nitrogen fixation, CO₂ conversion, methane activation, and others, driven by the contributions of researchers from diverse disciplines. Given that most research in this field is experimental, the methodologies employed play a pivotal role and demand careful consideration. However, due to the interdisciplinary nature of the field and variations in research objectives, available resources, and laboratory standards, experimental set-ups and approaches often differ significantly. Moreover, critical details regarding operational techniques and key methodologies are sometimes overlooked. This paper provides a comprehensive review of the methodologies and experimental approaches used in the study of plasma-based gas conversion for chemical production. It first examines experimental systems, including plasma reactor design, plasma-catalyst integration, and set-up configuration. Subsequently, operational schemes, conditions, and analytical procedures are discussed, with examples showcasing state-of-the-art advancements. Finally, discussion on emerging research trends and potential opportunities are presented, aiming to inspire further advancements and broaden the scope of this growing field.

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 nondominated 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.

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.

This study evaluates the techno-economic feasibility and environmental implications of integrating first-generation (1G) and second-generation (2G) bioethanol co-production using wheat grain and wheat straw (WS) as feedstocks. Three pretreatment methods—formic acid, sodium chlorite, and alkaline hydrogen peroxide (AHP)—were investigated, with AHP identified as the most industrially viable due to its mild conditions, high cellulose retention (73%), and reduced wastewater generation. The results indicated that the integrated 1G + 2G process exhibited high bioethanol production capacity (241300 t·y⁻¹) and mass yield (22.74%) under the conditions of 1200 t·d⁻¹ of wheat and 2000 t·d⁻¹ of WS. Furthermore, an energy recovery potential of 60.51%, alongside a 60.65% reduction in CO₂ emissions could be achieved. 1G + 2G process has a competitive minimum ethanol selling price (MESP: $431·t⁻¹), high internal rate of return (37%), and return on investment (76%). Life cycle assessment highlighted terrestrial ecotoxicity potential (35%) and freshwater ecotoxicity potential (32%) as dominant environmental impacts, driven by nitrogen fertilizer use and fuel combustion efficiency. Sensitivity analysis showed feedstock costs and ethanol pricing as critical economic drivers, while reducing nitrogen fertilizer application and optimizing combustion efficiency were key to mitigating environmental burdens. This work provides actionable insights for advancing integrated biorefineries with enhanced yield, economic viability, and sustainability.

Particle formulation engineering stands as a focal point of research and a critical trajectory within the chemical industry. In response to the challenges associated with antigen/drug delivery, our research group has proposed a suite of strategies centered on micro/nanoparticle platforms. This review integrates our investigations into the applications of particles across various dimensions in biomedical delivery systems. Specifically, it delineates the mechanisms by which particles augment vaccine-induced immune responses, notably through antigen cross-presentation, and the pivotal roles they play in facilitating drug-mediated targeting of cancer cells via confined mass transfer. This review also encompasses recent advancements in particle formulations, offering prospective insights into the utilization of chemical engineering principles in the design of nextgeneration biomedical delivery systems.

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.

Single-atom alloy catalysts represent a novel and advanced category of materials in heterogeneous catalysis, attracting considerable interest in electrochemical power storage and utilization because of the distinctive structural attributes and remarkable catalytic capabilities. By establishing atomically precise arrangements of catalytic centers on metallic surfaces, single-atom alloy create highly efficient active sites with near-perfect atomic utilization. The robust electronic coupling and geometric interactions between the atomic-scale precision sites and the supporting metal matrix impart exceptional catalytic properties, such as improved kinetic performance, precise molecular recognition, and prolonged operational durability. In essence, the structural integrity of the isolated metal active sites in single-atom alloy, combined with their precisely tunable coordination environments, substantially boosts the electrochemical performance and catalytic efficiency. This review begins by introducing and discussing the fundamental concepts and inherent attributes of single-atom alloy. The methodological framework for single-atom alloy development was systematically examined, encompassing architectural design principles, fabrication methodologies, and analytical characterization techniques. Following this, the comprehensive summarization was conducted regarding the implementation of single-atom alloy catalysts in energy transformation technologies, with specific emphasis on fuel cells and environmentally electrochemical processes. Finally, forward-looking insights and perspectives are presented on the current challenges facing the development of single-atom alloy catalysts.

The need for efficient energy storage systems has promoted the development of supercapacitors. Researchers have recently focused on building hybrid supercapacitors and synthesizing electrode materials using ecological and easily scalable methods. This work presents the development of hybrid supercapacitors based on cobalt ferrite-carbon composite. The spinel ferrite was synthesized by co-precipitation followed by heat treatment, and a ferrite-glucose precursor was used to obtain a mesoporous composite with a specific surface area of 41.195 m²·g⁻¹. Adding carbon does not structurally modify the cobalt ferrite but significantly improves the electrochemical properties. The electrochemical characterization in a three-electrode cell yielded a maximum specific capacitance of 548.1 F·g⁻¹ at a current density of 14.5 A·g⁻¹. The composite was mixed with sustainable activated carbon in different proportions to assemble solid-state hybrid supercapacitors. A maximum specific capacitance and energy of 69.8 F·g⁻¹ and 27.9 Wh·kg⁻¹ were obtained with a symmetric 1.2 V device, corresponding to a specific power of 94 W·kg⁻¹. These results show that it can develop hybrid supercapacitors based on the CoFe₂O₄-C composite, synthesized by a simple, low-cost, and environmentally friendly method.

Four different chelating agents, ethylenediamine tetraacetic acid, citric acid, glucose, and sucrose, were selected to synthesize MnCr₂O₄ catalysts (spinel structure) with sol-gel method. Among the prepared catalysts, MnCr₂O₄-S-700, which had the largest specific surface area, showed the best catalytic performance, with a T80 temperature window of 200–260 °C and a denitrification rate of up to 91.6% at 220 °C. Hydrogen temperature programmed reduction, ammonia temperature programmed desorption, and X-ray photoelectron spectroscopy results showed that MnCr₂O₄-S-700 possessed more chemisorbed oxygen O_α as well as active sites (Mn³⁺ + Mn⁴⁺) and (Cr³⁺ + Cr⁵⁺), which improved acidity and redox capacity. There was abundant electron transfer between Mn and Cr elements (Cr⁵⁺ + Mn³⁺ → Cr³⁺ + Mn⁴⁺), enhancing the redox capacity of catalysts. According to the in situ diffuse reflectance infrared transform spectroscopy spectra, it could be concluded that the MnCr₂O₄-S-700 catalyst followed not only the Langmuir-Hinshelwood mechanism but also the Eley-Rideal mechanism. This work displays the effect of the complexation mechanism of chelating agents on the SCR reaction with NH₃ over spinel catalysts.

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.