Frontiers of Chemical Science and Engineering最新文献

Catalytic pyrolysis technology, particularly using polyolefin plastic waste as feedstock, has emerged as a promising approach for transforming waste plastics into carbon nanotubes, not only reducing their production cost but also achieving efficient disposal and high-value utilization of plastic waste. This work reviews the research on the preparation of carbon nanotubes from various waste plastics and summarizes the influence of metals and support on catalysts. The design of reactors and the optimization of process conditions are also critical factors influencing the yield and quality of carbon nanotubes. The growth mechanism of carbon nanotubes is systematically elucidated, encompassing radical reactions during pyrolysis, carbon dissolution-precipitation dynamics on catalytic surfaces, and subsequent structural evolution. Collectively, this review underscores the significant potential of catalytic pyrolysis in advancing sustainable plastic waste management and high-value resource recovery.

Electrochemical carbon dioxide reduction reaction (CO₂RR) represents a pivotal strategy for sustainable carbon cycling and chemical synthesis. This review comprehensively analyzes the burgeoning field of two-dimensional (2D) metal nanosheets (e.g., Bi, Ag, Co, Pd, Cu) as high-performance electrocatalysts for CO₂RR. We delve into the fundamental catalytic mechanisms underpinning their activity across both gas-phase (e.g., CO, CH₄, C₂H₄) and liquid-phase (e.g., HCOOH, CH₃OH, C₂H₅OH) product formation pathways, with a particular focus on deciphering critical structure-activity relationships. Key intrinsic properties: composition, exposed crystal facets, and defect engineering, are systematically examined to elucidate their profound influence on catalytic activity, selectivity, and product distribution. Beyond mechanistic insights, the review critically assesses the practical utility of these 2D metal catalysts, highlighting emerging applications, persistent challenges (e.g., scalability, long-term stability, competitive reactions, C₂₊ selectivity control), and promising future research trajectories. By bridging fundamental catalytic principles with applied materials design, this work provides novel perspectives for advancing efficient and selective CO₂RR technologies crucial for achieving carbon neutrality goals.

Aside from being essential for human needs, water resources are also in demand by various industries to ensure the sustainability of economic development in countries. However, the supply of clean and affordable water is slowly depleting to the point where it becomes a major issue that requires significant attention. The membrane filtration system is an effective method for purifying water, with a high potential to provide clean water with minimal energy. The membrane spacer is a significant component in the membrane filtration system that considerably influences its performance. The dominant challenge in membrane spacers is fouling, mainly biofouling, which leads to unwanted consequences that drastically decrease the system’s performance. This review focuses on the advancements in membrane spacer technology through the modification of geometric design, selection of materials, and evaluation of their impact on fluid dynamics and biofouling. Additionally, the review provides insight into the utilization of three-dimensional printing methods and three-dimensional simulations in advancing membrane spacer technology.

This study proposes the synthesis, design, and control of a separation process for a concentrated ternary mixture of methanol, ethyl acetate, and water, which exhibits two minimum boiling azeotropes, to separate it into constituent nearly pure components. The proposed flowsheet leverages the presence of a liquid-liquid envelope by using a liquid-liquid extractor with recycled water as a solvent to strategically bring the initial feed point into the liquid-liquid split region, facilitating energyefficient separation. The design consists of a liquid-liquid extractor followed by a triple-column distillation sequence. Compared to the existing extractive heterogeneous azeotropic distillation process, the proposed process achieves savings of 36.9% in total annualized cost, 46.1% in reduced energy consumption, and CO₂ emission. Additionally, a regulatory plant-wide decentralized control structure has been developed through rigorous dynamic simulations, demonstrating its effectiveness in rejecting principal disturbances in throughput and feed composition.

Doped perovskite oxides are efficient electrocatalysts for water oxidation; however, the mechanism of O-site doping remains unclear. This study proposes a long-range electron-rich optimization mechanism for Cl doped LaCoO₃, involving the formation of ultra-long Co–Cl bonds as a result of lattice distortion induced by Cl doping at the O site. This catalyst exhibited excellent oxygen evolution reaction activity and stability. Theoretical calculations revealed that the ultra-long Co–Cl bond enables an electron-rich state at the Co sites, weakening the Co–O lattice bonding and facilitating the conversion of lattice O into bulk-phase O species, thus enhancing the performance of oxygen evolution reaction. This study introduces a novel regulatory mechanism for doped perovskite oxide catalysts to enhance water oxidation.

Heterogeneous catalysis is fundamental to chemical processes, with gas-solid catalysis extensively employed in chemical production, energy conversion, and environmental protection. Attaining high efficiency in these processes necessitates catalysts exhibiting exceptional activity, selectivity, and stability, frequently accomplished using nanostructured metal catalysts. The continuous growth of active sites in heterogeneous metal catalysts presents a considerable obstacle for the precise identification of the genuine active sites. The emergence of in situ and operando characterization techniques has clarified the knowledge of dynamic alterations in active sites, offering substantial scientific information to underpin the rational design of catalysts. This review summarizes recent progress in the development of diverse situ/operando approaches for identifying active regions in catalytic conversion over heterogeneous catalysts. We comprehensively outline the applicability of diverse optical and X-ray spectroscopic techniques, including transmission electron microscopy, Raman spectroscopy, ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy, in identifying active sites and elucidating reaction processes in heterogeneous catalysis. The discussion encompasses issues and future views on the identification of active sites evolution during the reaction process, as well as the advancement of in situ and operando characterization approaches.

Targeting the demand for efficient dehydrogenation catalysts in liquid organic hydrogen carriers, we synthesized a series of La-doped alumina supports by a co-precipitation/hydrothermal route and deposited Pd nanoparticles to promote 12H-N-propylcarbazole (NPCZ) dehydrogenation. Comprehensive characterization shows that an optimal 10 wt % La loading generates intimately interfaced La₂O₃ and La(OH)₃ nanodomains that anchor highly dispersed Pd particles (∼2.2 nm), donate electrons to Pd⁰, and create bifunctional acid-base sites together with a fast hydrogen-spillover network. These synergistic features accelerate C–H activation and H-migration, enabling Pd/La₁₀AlO to deliver the theoretical H₂ release (5.43 wt %) in 150 min at 180 °C with 99% NPCZ selectivity and no activity loss over ten cycles. Kinetic analysis reveals markedly lower apparent activation energies for all three successive dehydrogenation steps, with a ∼65 kJ·mol⁻¹ drop in the rate-limiting 4H-NPCZ→NPCZ stage, underscoring the thermodynamic and kinetic benefits conferred by the dual-phase La promoter. This work provides the first mechanistic evidence that coexisting La₂O₃/La(OH)₃ can cooperatively tune the electronic and interfacial structure of Pd/Al₂O₃, offering clear guidelines for designing durable, high-performance dehydrogenation catalysts for N-heterocyclic liquid organic hydrogen carriers.

High-purity glycolide is a key monomer for the synthesis of biodegradable polyglycolic acid. Here, we report a relay transesterification strategy for synthesizing high-purity glycolide directly from methyl glycolate, by using behenyl alcohol as a recyclable transesterification agent. This strategy achieves an average purity of 99.3% for glycolide without forming oligomers, and thus can avoid the energy-intensive purification required in the conventional route. Mechanistic studies indicate that methyl glycolate is first converted into behenyl glycolate via hetero-intermolecular transesterification during the relay transesterification process, and then the behenyl glycolate undergoes a homo-intermolecular transesterification to form behenyl dimer glycolate, which then undergoes intramolecular backbiting transesterification to yield glycolide and behenyl alcohol.

Perovskites have emerged as promising semiconductors for solar cells and optoelectronics. Despite rapid advancements in device performance over the past decade, a quantitative investigation into structure-property relationships remains absent. The core of these innovations in fabrication lies in controlling long-range and short-range microstructural disorders in perovskites, yet their systematic impact across multiple spatial scales remains underexplored. In this review, we elaborate on hidden microstructural disorders, including interfacial disorders and intra-crystal disorders, further delving into their formation mechanisms and effects on mechanical reliability and long-term operational stability of perovskites. Unraveling these effects requires a combined approach of theoretical modeling and experimental characterization. Furthermore, we discuss theory-driven engineering strategies to mitigate such microstructural disorders, enabling the predictable processing and fabrication of stable and high-efficiency perovskite solar cells. This review aims to establish a foundational framework for transitioning from microstructure observation to microstructure control, which represents a critical frontier in the advancement of perovskite photovoltaics.

Ammonia is a promising hydrogen storage carrier due to its high hydrogen density (17.8 wt %) and mild liquefaction conditions. Plasma-catalytic ammonia synthesis is an alternative synthesis route regarding green ammonia generation at ambient conditions. In this study, Co-doped Mo₂N-Co catalysts were developed to enhance plasma-catalytic ammonia synthesis, with a focus on the effects of Co/Mo molar ratios and operating parameters. Among the catalysts tested, Mo₂N-Co₁ possessed the highest ammonia synthesis rate and energy efficiency. Optimal operating conditions including a feed ratio of N₂:H₂ = 1:1 and a higher discharge power is favored. An ammonia synthesis rate of 11925 µmol·g⁻¹·h⁻¹ and an energy efficiency of 3.6 g-NH₃·kWh⁻¹ were achieved over Mo₂N-Co₁ at a feed ratio of N₂:H₂ = 1:1 and a discharge power of 57 W. Comprehensive characterizations, including X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, electron paramagnetic resonance, hydrogen temperature-programmed reduction, and ammonia temperature-programmed desorption, demonstrated that Co doping introduced abundant nitrogen vacancies and weak acidic surface, both of which facilitated ammonia desorption and electron transfer. Key reactive intermediates were identified using optical emission spectroscopy, providing insight into the proposed reaction mechanism for this synergistic plasma-catalytic ammonia synthesis over Mo₂N-Co catalysts.