Industrial Chemistry & Materials最新文献

As the polyurethane foam (PUF) market, especially in the automotive sector, continues to grow, the environmental impacts of its petrochemical demands and end-of-life waste have motivated the industry to look for more sustainable solutions. This study explores the preparation of recyclable PUFs using commercially available soy polyols (Cargill's BiOH), aiming to enable improved thermal reprocessability of flexible PUFs via vitrimer chemistry. A series of “soy-PUFs” was produced by partially substituting petrochemical polyether polyols with 25% or 50% soy polyols in a standard reference formulation. Incorporation of soy polyols resulted in an increase in the stiffness of the resulting foams. Employing a modest amount (∼0.5 wt%) of dibutyltin dilaurate (DBTDL) in the formulations facilitated dynamic covalent bond exchanges in the cross-linked network during a mild “foam-to-sheet” reprocessing process (160 °C), converting malleable PUFs into densified sheet materials (PUS) with proper compactness and mechanical performance (e.g., tensile modulus = ∼50 MPa). Soy-PUFs demonstrated a modestly enhanced stress relaxation behavior, suggesting adequate reprocessing ability. DMA results demonstrated the phenomenon of forming an “intermediate” region between the hard and soft domains of PUSs after reprocessing.

Keywords: Polyurethane foam; Soybean oil; Polyols; Vitrimer chemistry; Reprocessing; Recycling.

Electrochemical CO₂ reduction has favorable industrial relevance due to its integrability with renewable energies and controllable product generation. Bismuth-based catalysts have emerged as promising candidates in this regard due to their intriguing electrochemical properties and cost-effectiveness. This review focuses on recent advances in bismuth-based catalysts for the electrochemical reduction of CO₂, including synthesis methods and approaches for performance improvements. Insights into product formations using Bi-based catalysts are also presented, where in situ FTIR and Raman spectroscopic studies are highlighted to understand the structural evolution of the catalysts and to decipher the mechanisms of CO₂ reduction. Further, recent progress of electrochemical CO₂ reduction from an industrial perspective and strategies for further development of the bismuth-based catalysts with high activity, selectivity and stability towards practical applications are discussed.

Keywords: Electrochemical CO₂ reduction; Bismuth; Nanomaterials; Electrocatalysts; In situ spectroscopy.

A liquid thermoelectric conversion device (LTE) converts environmental heat into electric power via the electrochemical Seebeck coefficient α. The maximum power (W_max) is expressed as , where ΔT and R′ are the temperature difference between electrodes and device resistance in operation, respectively. Here, we systematically investigated the resistance components of LTEs composed of aqueous, methanol (MeOH) and acetone solutions containing 0.8 M Fe(ClO₄)₂/Fe(ClO₄)₃. We found that the charge transfer resistance R_ct of the MeOH LTE is the smallest among the three LTEs. We demonstrated that the W_max of the MeOH LTE is slightly larger than or comparable with that of the corresponding aqueous LTE. We further discussed the effects of the convection of an electrolyte on R′.

Keywords: Liquid thermoelectric conversion; Methanol; Resistivity components; Coated electrode.

Photocatalytic hydrogen evolution based on the use of carbon nitride (CN) catalyst offers a sustainable route to convert solar energy into hydrogen energy; however, its activity is severely restricted by the sluggish transfer of photogenerated charges. Herein, we report a novel approach involving boron (B) doping-induced π-electron delocalization in CN for efficient hydrogen (H₂) evolution. The as-prepared B-doped CN (BCN) catalyst presented an 8.6-fold enhancement in the H₂-evolution rate (7924.0 μmol h⁻¹ g⁻¹) under visible-light irradiation compared with pristine CN, which corresponded to an apparent quantum yield (AQY) of 14.5% at 405 nm. Experimental analysis and density functional theory (DFT) calculations demonstrated that B doping induced π-electron delocalization in conjugated CN rings to generate a new intermediate state within the band gap to provide a new transfer path for visible-light utilization, thus achieving the high separation and transfer of photoinduced carriers. This work provides a new approach to adjust the electronic structure of CN-like conjugated polymer semiconductors for efficient catalytic energy conversion.

Keywords: B doping; π-electron delocalization; H₂ evolution; Photocatalysis.

Ultra-high molecular weight polyethylene (UHMWPE, M_w > 10⁶ g mol⁻¹) has been prepared using slurry-phase titanium permethylindenyl-phenoxy (PHENI*) catalysts. Four strategies have been investigated for improving the melt processability of UHMWPE, which is the chief limiting factor to the applications of this high-performance polymer. 1) Active site engineering was used to explore the entanglement density in the resulting polymer, with substantially disentangled PE identified through thermal and rheological characterisation. 2) Hydrogen and ZnEt₂ were employed as chain transfer agents to modulate the polyethylene molecular weight and distribution (MWD). A sequential reactivity protocol using ZnEt₂ was able to produce bimodal UHMWPE with improved processability. 3) MWD tuning was further investigated using multisite catalysts, with the reaction conditions and Ti : Zr ratio able to control MWD to essentially arbitrary shapes. The inclusion of low molecular weight fractions into UHMWPE improves the processability without compromising mechanical characteristics. 4) Polymer-reinforced composite blends of UHMWPE with either HDPE or LDPE as a highly processable matrix were extruded and explored, with polymer miscibility and mechanical properties studied in detail.

Keywords: Ultra-high molecular weight polyethylene; Processability; Molecular weight distribution; Polymer composites; Chain transfer agents.

Currently, the practical application of liquid lithium-ion batteries faces challenges in meeting the requirements of high energy density and safety. To address concerns such as electrolyte leakage and flammability, solid polymer electrolytes (SPEs) have emerged as promising alternatives to liquid electrolytes. SPEs, particularly those synthesized via in situ polymerization processes, offer advantages in establishing robust interface contacts and compatibility with existing industrial production lines. However, the electrochemical stability of SPEs remains a hurdle for high-voltage lithium metal batteries (LMBs). To enhance interface uniformity, electrochemical stability, and thermal stability, researchers commonly employ fluorination strategies, thus expanding the potential of SPEs in high-voltage, long-cycling LMBs. Fluorine plays a crucial role in achieving these objectives due to its high electronegativity, polarization, outstanding dielectric properties, strong bond strength, stability, and hydrophobic nature. In this study, we delve into how fluorinated electrolytes improve interface stability between SPEs and electrodes by examining their underlying mechanisms. Besides, we provide an overview of current fluorination strategies and their impact on battery performance. Furthermore, we discuss challenges and issues associated with current in situ polymerized fluorinated SPE routes and propose practical strategies for consideration.

Keywords: Lithium metal batteries; In situ polymerization; Fluorinated polymer electrolytes; High-voltage; Long cycling; Stable interface.

Addressing the degradation of persistent organic pollutants like bisphenol A (BPA) and rhodamine B (RhB) with a photocatalyst that is both cost-effective and environmentally friendly is a notable challenge. This research presents the synthesis of an optimized g-C₃N₄/Bi₄O₅Br₂ composite featuring a Z-scheme heterojunction structure. The precise band alignment of this composite significantly enhances the separation of photogenerated charges and the production of dominant reactive species. The composite demonstrated exceptional photocatalytic performance, with BPA degradation efficiency nearing 98% and RhB achieving complete degradation within 80 and 35 min under visible light, respectively. These results are approximately 1.3 times greater than the individual performance of CN and BOB, surpassing recent literature benchmarks. Through EPR and free radical capture experiments, the role of h⁺ and ·O₂⁻ as the primary active free radicals in the degradation process have been confirmed. First-principles calculations validated the experimental results, indicating that the Z-type heterojunction is instrumental in generating active species, thus improving degradation efficiency. This study offers a promising strategy for the design of photocatalysts targeting emerging organic pollutants.

Keywords: Photocatalysis; g-C₃N₄; Bi₄O₅Br₂; Heterostructure; Water purification; Z-scheme.

Sequential paired electrosynthesis capable of the production of organic chemicals through a series of electrochemical reactions that occur consecutively and in pairs are of high significance. Herein, a three-dimensional porous carbon felt-loaded PbO₂ electrode (PbO₂/CF) with a self-supported nanostructure was fabricated using a double-cathode electrodeposition method, which served as an efficient electrocatalyst enabling the unique sequential paired electrosynthesis of 1,4-hydroquinone (1,4-HQ) from phenol in a membrane-free electrolytic cell. In such an exotic paired electrolysis system, phenol is first oxidized to p-benzoquinone at the anode, which is subsequently reduced to 1,4-HQ at the cathode. The as-obtained PbO₂/CF electrode exhibited a remarkable electrochemical performance, achieving impressive conversion and selectivity of 94.5% and 72.1%, respectively, for the conversion of phenol to 1,4-HQ. This exceptional performance can be attributed to the open porous self-supported structure of the PbO₂/CF electrode, which improves the active site exposure and substrate adsorption capability and reduces mass and charge transfer resistance. Furthermore, the catalyst electrode well maintained its structure integrity even after 140 hours of long-term use, further highlighting its promising application for the electrosynthesis of 1,4-HQ. Moreover, this sequential paired electrosynthesis strategy can be further extended to other substrates with electron-withdrawing/donating groups over the PbO₂/CF electrode. The proof of concept in this innovative sequential paired electrosynthesis could provide a sustainable and efficient way to produce various desired organic compounds.

Keywords: Phenol; 1,4-Hydroquinone; Electrocatalysis; Sequential paired electrosynthesis; Self-supported electrodes.

Amidoxime-functionalized polymeric adsorbents have attracted great interest for uranium extraction from seawater. However, the current graft polymerization method is time-consuming (2–6 h), wasteful in reagent, and hence not economical. Here, amidoxime-functionalized adsorbents based on low-cost polypropylene melt-blown nonwoven fabric (MBF) are produced by a simple, fast and also low-cost surface photografting technology, by which more than 80% of reagents can be saved and grafting time can be reduced to 3 min. The fabricated adsorbents retain their mechanical properties and exhibit excellent uranium adsorption properties, with a maximum uranium adsorption capacity of 400 mg g⁻¹ when the monomer ratio of AN to AA is 8 : 2. Moreover, we showed that the adsorbents could be either reused or simply incinerated for uranium recovery. The photografting technology has great potential for low-cost, continuous industrial production of uranium-adsorbing material.

Keywords: Uranium extraction from seawater; Amidoxime; Nonwoven fabric; Surface photografting.

Acid-, base-free depolymerization of poly(ethylene terephthalate) (PET) with ethanol catalyzed by FeCl₃, FeBr₃ (1.0–5.0 mol%) gave diethyl terephthalate (DET) and ethylene glycol (EG) exclusively (98–99%, 160–180 °C), and FeCl₃ showed better catalytic performance in terms of activity. The FeCl₃ catalyst enabled exclusive, selective depolymerization of PET from textile waste to afford DET (and recovered cotton waste), strongly suggesting the possibility of chemical recycling of cloth waste by the transesterification in this catalysis.

Keywords: Depolymerization; PET; Chemical recycling; Textile waste management; Homogeneous catalyst.