Frontiers of Chemical Science and Engineering最新文献

In the past decades, the advancement of sensor technology has enabled the development and application of reliable process analytical technology in pharmaceutical manufacturing for process monitoring and control. Soft sensors as mathematical models are often coupled with process analytical technology tools to monitor critical quality attributes such as concentrations and particle sizes. Crystallinity and polymorphism changes are prevalent phenomena in pharmaceutical manufacturing. These changes may impact drug manufacturability, drug quality, and patients’ safety. Therefore, assessment of impact of crystallinity and polymorphism change has been one critical aspect of pharmaceutical chemistry, manufacturing, and control review and inspection. Chemistry, manufacturing, and control risk assessment has been largely qualitative in nature and has heavily relied on past knowledge and experience. The potential use of soft sensors to monitor such changes and establish a science supported risk-based control strategy is not widely discussed. In this work, by applying soft sensor models to key unit operations, we presented case studies to discuss the capability and potential of soft sensors in predicting critical quality attributes for key pharmaceutical unit operations, including crystallinity and polymorphism changes in selected drugs with moderate to high solid-state risk levels in drug product manufacturing. Population balance models, semi-empirical models, and statistical correlations are applied to wet granulator, fluidized bed dryer, mill, and tablet press to enable soft sensing. Sensitivity analysis using the established models is conducted to quantitatively assess the impacts of process inputs onto different outputs to support a risk-based control strategy with regulatory insights. Knowledge, experience, and discussion in these aspects can contribute to the future development of advanced technologies and the implementation of modeling tools toward advanced manufacturing.

Medium- and low-temperature thermochemical energy storage materials are vulnerable to deliquescence, agglomeration, and structural fracturing under hyperhumid conditions, yet the fundamental origins of excess environmental moisture within reactors remain insufficiently characterized. This study systematically elucidates water vapor transport mechanisms between air and physical adsorption materials in thermochemical reactors, with emphasis on transient humidity transfer phenomena during incomplete charging and discharging cycles. Moisture saturation was defined as the key parameter for standardized humidity analysis. Results indicate that uncontrolled saturation arises from thermally driven vapor depression, in which water vapor desorbed from materials or transported by inlet air undergoes progressive condensation during downstream migration. Moisture saturation dynamics were governed by coupled effects of inlet air temperature, flow velocity, and relative humidity. Reverse charging was shown to effectively reduce maximum moisture saturation in cases where materials remained incompletely hydrated after prior discharging. Optimization of inlet air conditions through controlled transitions from low-temperature, high-velocity states to a predesigned charging protocol achieved a 45.7% reduction in maximum moisture saturation (from 1.38 to 0.75). In addition, preheating prior to discharging significantly suppressed reactor moisture saturation, thereby mitigating material failure risks.

Perturbed-chain statistical associating fluid theory has emerged as a powerful thermodynamic framework for predicting drug-polymer miscibility and stability in amorphous solid dispersions. This review provides a comprehensive overview of the theoretical foundations of perturbed-chain statistical associating fluid theory, including its forma, the meanings of key parameters in physics, and common strategies for parameterization. Its applications to solid–liquid and liquid–liquid equilibrium calculations are highlighted, particularly in the construction of phase diagrams and the prediction of phase separation phenomena such as amorphous-amorphous and liquid–liquid phase separation. The utility of perturbed-chain statistical associating fluid theory in amorphous solid dispersions is illustrated through its roles in solubility prediction, stability assessment, drug release mechanism analysis, and rational formulation and process design. In addition, perturbed-chain statistical associating fluid theory is critically compared with alternative predictive methods, including solubility parameter theory, Flory–Huggins models, molecular simulation approaches, and machine learning. Finally, this review outlines the key challenges and future directions for integrating perturbed-chain statistical associating fluid theory with data-driven and multi-scale modeling approaches to advance model-informed amorphous solid dispersion design.

The electrocatalytic co-reduction of carbon dioxide (CO₂) and nitrate (NO₃⁻) to urea represents a sustainable alternative to energy-intensive industrial synthesis processes. Herein, we report copper-doped cerium oxide nanorods (Cu-CeO₂) as an efficient catalyst for this reaction, achieving a urea yield of 358.5 mg·h⁻¹·g⁻¹ at −0.7 V vs. reversible hydrogen electrode with 21.1% Faradaic efficiency. In situ Fourier transform infrared spectroscopy analysis reveals that during electrocatalytic urea synthesis, CO₂ activation at the catalyst surface generates carbonyl-containing intermediates (*CO), which couple with nitrogenous species (NH_x) derived from NO₃⁻ reduction. The key coupling reaction intermediate *NHCO was detected, and the *NHCO intermediate played a crucial role in promoting C–N bond formation. The stability of this intermediate directly facilitated the successful formation of urea. These findings elucidate the reaction pathway mediated by the Cu-CeO₂ catalyst, establishing a theoretical foundation for subsequent catalyst design optimization.

BiVO₄, with its moderate band gap (∼2.4 eV) and visible light absorption properties, is considered a promising photoanode material. However, its photoelectrochemical performance is hindered by intrinsic defects such as poor charge carrier transport and rapid electron-hole recombination, resulting in a significant gap between its practical and theoretical photocurrent densities. In this work, we present a simple surface reconstruction method by adding citric acid to Na₂SO₄ electrolyte. Citric acid’s multidentate structure strongly chelates the metal-sites on the BiVO₄ surface, triggering lattice reconstruction through intense interactions. This surface modification not only prolongs hole lifetime but also acts as an interface modifier, leaving a carboxyl-rich, superhydrophilic interface on the BiVO₄ surface after the reaction (contact angle ≈ 0°). The multi-dimensional optimization synergistically improves BiVO₄’s photoelectrochemical performance, achieving an excellent photocurrent density of 6.8 mA·cm⁻² under AM 1.5G irradiation. Importantly, our findings reveal a three-pronged synergy achieved with inexpensive citric acid: structural reconfiguration, electronic tuning, and extreme wettability, which offered a streamlined route for solar fuel production without solid co-catalysts.

The rapid advancement of flexible electronics creates an urgent demand for high-performance printed electronic materials. MXene-based inks have been widely studied and used for screen-printing electronics, while they usually suffer from poor screen-printability and inadequate mechanical properties of the printed coatings. Therefore, we incorporate 2,2,6,6-tetramethylpiperidinooxy oxidized cellulose nanofibers into MXene ink to regulate its rheology and enhance printability on both porous A4 paper and compact polyethylene terephthalate substrates. The introduction of cellulose enables precise control over the rheology and microstructure of the resultant MXene coatings. Critically, the strong interfacial hydrogen bonding and physical entanglement between cellulose and MXene contribute to the substantial enhancements of the mechanical properties and structural stability of the resultant composite coatings, where a remarkable 9.04-fold increase of hardness and a 1.74-fold increase of Young’s modulus are achieved. The interfacial binding strength between the coating and substrate is also well enhanced with the anchoring of cellulose. This work thereby presents a promising strategy for the design and fabrication of flexible screen-printed electronics.

Polyimide membranes, owing to their robust polymer backbone and facile structural tunability, are extensively used for H₂/CO₂ separation. However, efficient H₂ separation remains challenging because of the wide pore size distribution within the chain-packed structure of conventional polyimides. Here, we propose a coordination crosslinking engineering strategy, where Pd²⁺ is incorporated into an alkynyl-based polyimide containing carboxyl groups to generate coordination cross-linked networks in situ. The formed coordination bonds significantly reduce the interchain d-spacing and restrict the mobility of the polymer chains, thereby enhancing size-sieving ability. Additionally, the presence of Pd²⁺ significantly increases the affinity of membrane for H₂. Based on their synergistic effect, the optimized EBPA-TB-COOH@Pd²⁺-6 membrane (EBPA: 4,4′-(ethyne-1,2-diyl) diphthalic anhydride; EBPA-TB-COOH: alkynyl-based polyimide polymer) exhibits an unprecedented combination of high H₂ permeability (512.5 bar) and excellent H₂/CO₂ selectivity (30.4), surpassing most polyimide membranes reported to date. Furthermore, the coordination crosslinking networks endow the membranes with high and stable H₂/CO₂ separation performance under a wide operating pressure range (1 to 6 bar). This coordination crosslinking engineering strategy offers an effective approach for designing next-generation polyimide membranes for hydrogen recovery and purification.

This study explores fractional and simultaneous precipitation methods to recover metals from a synthetic solution containing the major components from lithium-ion battery recycling leachates: Co, Ni, Mn, Li, and H₂SO₄. Thermodynamic simulations analyzed the behavior of the metal-bearing solutions during hydroxide precipitation to guide process design. The fractional precipitation process was divided into three steps: pH-adjustment (D1), Co and Ni recovery (D2), and Mn recovery (D3). D2 achieved 89.7% Ni and 76.8% Co recovery; alongside Mn and Li were also removed (15% and 25% respectively). D3 showed mainly Mn recovery (68%) along with 18.7% Co and 7.3% Ni. Simultaneous precipitation resulted in over 99.7% recovery of Co, Ni, and Mn, with a small amount of Li (15%) being recovered from the solution. Na removal from the solution was observed across all experiments. X-ray diffraction analysis revealed that the phases formed were distinct from the predictions. Regardless of the presence of NH₄OH as a chelating agent in solution, a mixed nickel-cobalt-manganese oxide could be obtained after calcination. This approach offers a potentially less laborious method for recovering metals in products relevant to cathode precursors in a single step from recycling leachate.

Addressing electron and gas transfer dynamics is pivotal for photocatalytic hydrogen evolution. In this work, a hydrophilic NiCo₂O₄/CdS heterojunction was incorporated with hydrophobic SiO₂ to enhance photocatalytic hydrogen evolution performance. The hydrophilic/hydrophobic NiCo₂O₄/CdS/SiO₂ photocatalyst exhibited a hydrogen production rate of 11.78 mmol·g^-1·h^-1, outperforming the 8.15 mmol·g^-1·h^-1 of NiCo₂O₄/CdS heterojunction. The heterojunction significantly enhances photogenerated charge-carrier separation efficiency, while the hydrophobic SiO₂ facilitates gas evolution by mitigating surface bubble aggregation. The work here provides a facile route for developing photocatalysts toward practical hydrogen evolution.

Currently, the electrocatalytic two-electron oxygen reduction reaction for the production of H₂O₂ presents a promising alternative to the energy-intensive anthraquinone process. Enhancing the selectivity and activity of the catalyst is crucial for achieving efficient electrosynthesis of H₂O₂. Transition metal compound catalysts are considered ideal electrocatalysts due to their advantages, including simple preparation, low cost, diverse crystal structures, abundant availability, environmental friendliness, and the synergistic effects between coupled metals. This paper systematically reviews the latest research advancements regarding transition metal compounds used in oxygen reduction reactions to generate H₂O₂. It begins by elaborating on the fundamental concepts related to oxygen reduction reactions and subsequently discusses various methods for regulating transition metal compound catalysts, including element doping, defect generation, heterogeneous structure construction, crystal design, and polycrystalline transformation. The activities, selectivity, and stability of different transition metal compounds in the electrocatalytic synthesis of H₂O₂ are summarized, and the future development directions for transition metal compound catalysts are explored, providing valuable insights for the large-scale and efficient electrosynthesis of H₂O₂ in the future.