Developing efficient photocatalysts for hydrogen peroxide (H2O2) photosynthesis driven by natural sunlight is of great interest. In this study, we designed two photoactive donor (D)-acceptor (A) type truxene-based porous aromatic frameworks (Tx-PAFs) by introducing different electron acceptors as linker units. It was found that fluorenone-linked Tx-PAF with stronger D-A interaction exhibits a broader light absorption range and enhanced charge separation. This Tx-PAF displayed the superior photocatalytic H2O2 production with the rates of 3443 μmol g-1 h-1 (O2 atmosphere) and 1153 μmol g-1 h-1 (air) under Xe lamp irradiation. Notably, it can also achieve an H2O2 production rate of 716 μmol g-1 h-1 even under natural sunlight irradiation. This work provides feasible access to designing efficient and stable PAF-based photocatalysts for H2O2 production directly driven by solar energy.
This study explores the use of amino acids as renewable curing agents for the synthesis of fully biobased epoxy thermosets derived from triglycidylether of resveratrol (TGER). Combining the multifunctionality of amino acids with the aromatic rigidity of resveratrol, high-performance sustainable thermosets were designed. To increase the green metrics, series of TGER/amino acid formulations were prepared and polymerized under controlled thermal conditions consistent with green chemistry principles. Differential scanning calorimetry and temperature-assisted FTIR analyses demonstrated complete functional conversion and network formation through amino ether and ester linkages while dynamic mechanical analysis revealed that the prepared thermosets show glass transition values between 115 and 250 °C and high storage moduli up to 3.6 GPa. Among the examined systems, aromatic amino acids such as tyrosine, tryptophan, and histidine produced the most rigid and performant materials. Tensile and hardness tests confirmed that the designed thermosets are tough, moderately brittle, with Shore D values up to 87. Thermogravimetric and moisture absorption analyses indicated good thermo-oxidative resistance and low water uptake for aromatic amino acid-based networks. Overall, the study underscores the feasibility of achieving high-performance, sustainable thermosets using amino acids as curing agents, supporting the transition toward fully biobased polymers.
Plastics have numerous applications in industrial and household purposes. Thus, their annual production is increasing, thereby generating enormous end-of-life waste. Very often, these polymeric wastes are typically buried underground or discharged into the ocean and is alarming. Notably, recycling rates of such polymers are extremely low; therefore, sustainable solutions for recycling of polymers attracted significant attention. Herein, we have demonstrated a general and sustainable transfer hydrogenation strategy for the depolymerization of carbamates and ureas, including polyurethanes (PU)-the polymeric analogs of carbamates-and lab-made polyurethanes enabled by nickel. A variety of end-of-life PU wastes generated from bike seats and kitchen sponges have been depolymerized into speciality chemicals, such as aromatic diamine and polyols. Catalytic protocols exhibited a broad scope (>52 entries, up to 99% yield) and remarkable functional group tolerance. Mechanistic studies and control experiments were performed to understand the catalytic pathways.
A series of new deep eutectic solvents (DESs) was prepared to enable a greener approach to cellulose recovery from cotton products and textile waste. In this context, while choline-based binary DESs have been extensively investigated, alternative systems, especially metal-based hydrated DESs, have received less attention. In this work, four novel ternary DESs were synthesized using (i) ZnCl2 or CaCl2 and (ii) lactic acid or tartaric acid, (iii) with water added as a third component. By combining the hydrogen bond-disrupting capacity of traditional binary DESs with the lubricating-modifier and stabilizing effects of water, low-viscosity DESs, stable at room temperature, were obtained. These systems demonstrated remarkable versatility in processing cellulose from different sources, enabling complete dissolution of microcrystalline cellulose (MCC) and extensive structural disruption of cotton fibers to recover regenerated cellulose or nanocellulose (NC). The DES formulations were characterized through thermal and rheological analyses, including differential scanning calorimetry (DSC). The thermal stability, morphology, and structural changes of the processed cellulosic materials were investigated using thermogravimetric analysis (TGA), Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), polarized light microscopy (PLM), and electron microscopies (TEM and SEM/EDX). Overall, these results highlight the potential of earth-abundant, cost-effective metal-based DESs for the sustainable valorization of cotton-derived waste.
We report a ZIF-67-derived N-doped carbon-encapsulated cobalt catalyst (Co@N-C) for the efficient, reusable, and noble metal-free aerobic oxidation of concentrated aqueous 5-hydroxymethylfurfural (HMF) derivatives in a stepwise fashion to furan-2,5-dicarboxylic acid (FDCA). Using acetal-protected HMF with propane-1,3-diol (PD-HMF) to suppress degradation at high substrate concentrations, Co@N-C-800p (Co-containing ZIF-67 pyrolyzed at 800 °C) delivers high yields in water while enabling effective PDO recovery. At 20 wt% PD-HMF, a 96.8% yield of PD-FFCA (acetal-protected form of FFCA, 5-formylfuran-2-carboxylic acid) was obtained at 99.2% conversion. Subsequent deprotection afforded FFCA and enabled recovery of propane-1,3-diol, after which FFCA was oxidized separately under the same conditions to FDCA in a 93.6% yield. Replacing soluble alkali carbonates with sparingly soluble Ca(OH)2 provides buffered alkalinity that enhances formyl group oxidation, minimizes by-products, and limits PDO loss at reduced base loadings. Radical scavenger experiments indicate a mechanism involving oxygen-derived species that regenerate metallic Co sites via hydride removal. Although partial deactivation occurs through cobalt surface oxidation and CaCO3 accumulation, full catalytic performance is restored by re-pyrolysis. Overall, this work establishes Co@N-C as an efficient, stable, and regenerable non-noble metal catalyst for aerobic FDCA production at industrially relevant substrate concentrations.
Covalent adaptable networks (CANs) offer a promising route toward sustainable polymers by addressing the inherent conflict between thermoset performance and thermoplastic reprocessability through exchangeable covalent bonds. This review highlights a bio-based synthetic approach utilizing functionalized furan-maleimide Diels-Alder adducts, derived from furfural, as preformed monomers for polyurethane CANs. Unlike conventional postpolymerization crosslinking, this adduct-based strategy allows predictable incorporation of dynamic motifs into the backbone. This enables precise control over network topology and crosslink density while advancing sustainability through renewable feedstocks and recyclable network design. We demonstrate the advantages of the adduct-based approach and establish structure-property relationships that yield materials combining thermoset-like mechanical properties with stimuli-triggered self-healing, shape memory, and recyclability. Emerging applications in 3D/4D printing, UV-curable and waterborne coatings, and debondable adhesives are surveyed. Persistent challenges, including thermal and chemical instability of furanic and maleimide components, high activation barriers for network rearrangement, reliance on nonrenewable comonomers, and potential toxicity concerns, are also discussed. Future directions emphasize rationally designed multidynamic networks, robust dienophiles, and nonisocyanate routes to bridge academic innovation and industrial viability toward fully circular polymer systems.
Solvents are essential components for organic synthesis and are widely used across various industries. However, conventional solvents are frequently toxic volatile organic compounds (VOCs) that contribute significantly to waste generation and environmental pollution. This has driven the need to develop sustainable alternatives that maintain efficacy without the associated hazardous properties. Propylene carbonate (PC) has emerged as a promising green alternative for sustainable organic synthesis. As a polar aprotic solvent with similar physicochemical properties to acetonitrile and acetone, PC has been shown to afford high yields and selectivities comparable to those of traditional solvents in a wide range of synthetic transformations. It possesses favourable characteristics, such as low toxicity, high dielectric constant and solvation capacity, biodegradability and low vapour pressure. High thermal stability provides significant capacity for reusability across multiple reaction cycles with minimal loss of efficiency, a crucial feature for reaction scale-up. Moreover, PC can be readily prepared from propylene oxide and carbon dioxide, an abundant waste greenhouse gas, in a 100% atom-economical process. With an increasing number of reports on the topic, this paper presents an updated review of both the preparation and applications of PC, addressing methodological advances and new transformations.
Photocatalytic dehydrogenative coupling of biomass-derived furfuryl alcohol (FA) provides a promising route for simultaneous biomass upgrading and solar-to-chemical energy conversion. Herein, two novel isostructural Fe-containing polyoxometalates (POMs), FeII 2(H2O)6H19[FeIII 7SbV 4(H2O)12W6O20K2(C4H2O6)2(B-β-SbIIIW9O33)6]·55H2O (1) and FeII 2(H2O)6Na4H11.8[FeIII 8.6(H2O)16W8.4O22Na2(B-β-BiIIIW9O33)6]·41H2O (2), were synthesized via a one-pot solvothermal method and coupled with CdS nanorods (CdS NRs) to construct hybrid photocatalysts for FA conversion under 450 nm LED irradiation. Among them, 1/CdS exhibited superior performance, achieving 78.95% FA conversion, 85.91% selectivity toward hydrofuroin (HDF), and efficient H2 evolution (13.49 μmol). Structural and mechanistic studies revealed that the synergistic interaction between CdS NRs and Fe-containing POMs promotes charge separation and migration, thereby enhancing photocatalytic efficiency. This work highlights the potential of transition-metal-functionalized POMs for integrated biomass valorization and solar fuel production.
Living organisms have evolved multienzyme complexes to achieve efficient and spatially ordered metabolic reactions. Recently, liquid-liquid phase separation (LLPS) has emerged as a fundamental organizational principle underlying these natural networks, providing a versatile platform for constructing artificial multienzyme catalytic systems. Owing to their reversible self-assembly and programmable nature, LLPS condensates can modulate enzyme distribution, mass transfer, and the reaction microenvironment, thereby significantly enhancing catalytic efficiency and cascade reaction throughput. This review systematically summarizes recent advances in in vitro LLPS-based multienzyme catalytic systems. We introduce the fundamental phase separation behaviors of multienzyme condensates and their molecular interaction mechanisms. Then, diverse construction strategies are discussed based on distinct intermolecular forces and their applications in cofactor recycling, biosynthesis, biodegradation, and artificial organelle fabrication are highlighted. Furthermore, we dissect the core mechanisms of catalytic enhancement, including local molecular enrichment, microenvironment modulation, and spatial confinement. Finally, we discuss current limitations and offer future perspectives for the rational design of advanced, high-efficiency multienzyme biocatalysts.
Rechargeable magnesium batteries (RMBs) have attracted extensive attention as promising postlithium energy storage systems owing to their high volumetric capacity, intrinsic dendrite-less plating behavior, low cost, and natural abundance. Nevertheless, their practical implementation is severely hindered by persistent interfacial challenges, including the formation of surface passivation layers, sluggish Mg2+ transport kinetics, and continuous parasitic electrolyte decomposition. To address these issues, extensive efforts have been devoted to artificial interface engineering for stabilizing Mg metal anodes. Recent advances demonstrate that halide-rich artificial interphases, alloy-based artificial interphases, polymeric artificial interphases, and organic/inorganic hybrid interphases can fundamentally reconstruct Mg interfacial electrochemistry. These artificial interphases effectively regulate Mg2+ solvation structures, homogenize interfacial electric fields and ion flux distributions, suppress electrolyte decomposition, and promote highly reversible Mg plating/stripping behavior. In this review, we systematically summarize the recent progress in artificial interface engineering for Mg metal anodes, with emphasis on halide, alloy, polymeric, and hybrid interfacial systems. The underlying design principles, interfacial regulation mechanisms, and electrochemical functionalities are comprehensively discussed from the perspectives of Mg2+ transport, charge redistribution, solvation regulation, and mechanical stabilization. Finally, the remaining challenges and future opportunities toward scalable and high energy density RMBs are critically outlined.
A significant challenge associated with antibiotics, and active pharmaceutical ingredients in general, is their intentional design for high stability, which promotes environmental persistence and contributes to the development of antibiotic resistance. Ciprofloxacin, a widely used fluoroquinolone antibiotic, exemplifies this issue. Using the benign by design (BbD) approach, ciprofloxacin was redesigned into an environmentally improved fluoroquinolone molecule, termed Cip-hemi. In this design, ciprofloxacin was modified by replacing the persistent cyclopropyl group at the N1 position with a tetrahydrofuran moiety, thereby creating a degradable linker. Herein, we report the development of an efficient and robust synthetic platform to access the Cip-hemi scaffold, along with the preparation of a series of novel derivatives. These molecules are developed with a dual-purpose design: to restore high-level antibacterial action while ensuring rapid degradation in the aquatic environment. The optimized synthetic strategy minimizes the use of hazardous solvents and largely avoids labor-intensive purification by flash chromatography, providing a streamlined approach for the preparation of environmentally improved fluoroquinolones.
Plastic waste poses a major environmental challenge, yet it also represents a valuable feedstock to produce high-value chemicals. In this work, we report an ecofriendly and efficient mechanochemical strategy for upcycling of bio- and fossil-based polyesters under mild conditions into synthetically useful building blocks. Bio-based polyethylene furanoate (PEF), polybutylene furanoate (PBF), and polylactic acid (PLA), as well as fossil-derived polyethylene terephthalate (PET), were successfully transformed into their corresponding transesterification and amidation products in excellent yields using sodium methoxide as a catalyst. These reactions generate the corresponding diol, methanol, and sodium chloride as byproducts, which can be recovered and reused. Furthermore, using the same protocol, PEF was converted into bio-based plasticizers, including diethylhexyl furanate (DEHF) and diisoamyl furanoate (DIAF) in excellent yields. Importantly, the method is not limited to pure polymers but is also effective for commercially available PET- and PLA-based packaging materials. The products were isolated by simple aqueous workup and characterized using NMR, IR, HRMS, and XRD techniques. Overall, this mechanochemical route offers a sustainable, cost-effective, and versatile approach for polyester waste valorization, contributing significantly to a circular plastic economy.
Fluorinated compounds support several essential functions in rechargeable batteries, including salt dissociation, interphase formation, voltage stabilization, and electrode cohesion. Their extensive use, however, is accompanied by hydrolytic instability, corrosive decomposition products, persistent fluorinated residues, and difficulties in electrode recycling. This review evaluates strategies for reducing or eliminating intentionally introduced fluorine in electrolyte and binder systems for lithium- and sodium-based batteries. Fully fluorine-free formulations are distinguished from fluorine-reduced systems, and representative salts, solvents, additives, solid/quasisolid electrolytes, and aqueous binders are compared in terms of ion transport, voltage tolerance, interfacial chemistry, safety, and practical applicability. Particular attention is paid to the tradeoff between interphase stability and impedance, as well as to the scalability and end-of-life compatibility of aqueous electrode processing. Finally, priorities are proposed for realistic full-cell evaluation and coordinated material, manufacturing, and recycling design.
We present a detailed mechanistic analysis of thermal pyrolysis of linear and branched polyolefins. The pyrolytic pathways in high-density polyethylene (HDPE), polypropylene (PP), and linear low-density polyethylene (LLDPE) are compared. The mechanistic model for LLDPE is newly developed, based on the population balance approach incorporating reactions on the branches as well as the main chain. Specific reactions are unfurled based on a compact number of reaction families, each of which is governed by a structure/reactivity relationship to specify the activation energy of individual reactions and statistical mechanical estimates to quantify the Arrhenius pre-factor. The results from the model for LLDPE are compared to new data collected from micropyrolysis experiments that quantify detailed temporal product distributions. PP is confirmed as the most reactive of the three polymers, making the highest amount of low molecular weight products at a given time. For LLDPE, branches serve as positions for hydrogen abstraction, opening up new pathways for deconstructing the main chain. The length of the branches in LLDPE is shown to influence the degradation rate. Understanding the connection between structure and reactivity can help design polymer topologies and pyrolysis reaction conditions to optimize the recycling process and thus the product yields and selectivities.
Engineered microbial systems offer a route for converting lignin into value-added aromatics, yet lignin-derived intermediates are cytotoxic and suppress growth and metabolic flux. Here, we show that ectoine, a compatible solute, mitigates lignin-induced stress in Halalkalibacterium ligniniphilum L1 and improves bioconversion performance. At 0.1 g L-1, ectoine alleviated surface damage, improved chemical oxygen demand (COD) removal from about 40% to about 55%, and increased decolorization from about 25% to about 48%-50% over 7 days. Assays using crude extracts from recombinant Escherichia coli expressing individual L1-derived enzymes showed that ectoine was associated with broader apparent pH and temperature operating ranges, up to a 12.3% point increase in fixed time substrate conversion, and improved time-dependent retention of measurable activity. Transcriptomic analysis identified 24 differentially expressed genes (9 upregulated and 15 downregulated; false discovery rate (FDR) < 0.05, |log2 fold change (log2 FC) | ≥ 1), indicating a focused rather than global response. Ectoine-responsive changes were associated with membrane/envelope-related functions, transport, and oxidoreductase-related processes, whereas motility and generalized stress-associated programs were reduced. In a 5-L bioreactor, ectoine increased vanillin titers by 13.9%-23.0% at lignin concentrations of 20-40 g L-1. These results support ectoine as an additive for lignin bioconversion under stress.
Commercial FCC catalysts (fresh and equilibrated) and laboratory made catalysts from Y type zeolite and γ-Al2O3 are characterized by standard techniques and evaluated in the cracking of pure PP, LDPE, and PS polymers as well as coprocessing PP/LDPE mixture in TGA (light-off curves) and a unique operando FTIR & GC-MS set-up. Conversions, products selectivities as well as coke deposition and removal are studied as a function of temperature. In spectroscopic operando investigations, MCR-ALS analysis provides significant insight into the observed results. The equilibrium FCC catalyst (Cat-Eq800) differs markedly from its fresh counterpart (Cat-F800) in product selectivity. Regardless of the polyolefin feed, Cat-Eq800 exhibits higher olefinicity in the C4 fraction. In both commercial catalysts, coke precursor formation proceeds predominantly via paraffin consumption. In situ FTIR analysis revealed valuable information regarding reactant diffusion and catalyst acidity. Despite undergoing severe deactivation treatments, the equilibrium catalyst displays the highest Brønsted-to-Lewis acid site ratio while maintaining efficient mass transport through its hierarchical pore structure. Important information to better design FCC catalysts can be derived, as the exact composition of these important catalysts are often tailored for specific families of heavy oil fractions.
Room temperature phosphorescence (RTP) materials derived from sustainable resources are highly desirable but remain challenging due to the intrinsic instability of triplet excitons under ambient conditions. Herein, a biobased RTP system is reported by selectively integrating chlorogenic acid-derived carbon dots (CDs) into a cellulose-rich coconut coir matrix. The coir fiber, after oxidative delignification, forms a rigid and dense hydrogen bond network that effectively confines the emissive CDs and suppresses non-radiative decay. The incorporation of CDs not only introduces tunable emissive states but also enables stable phosphorescence through synergistic interactions with the matrix, achieving lifetimes up to 529.07 ms under ambient conditions. The phosphorescence color can be continuously tuned from green to orange-yellow by varying the precursor composition, while excitation-dependent afterglow further enables multicolor phosphorescence from a single material. Furthermore, the materials exhibit excellent processability and can be fabricated into films, fibers, powders, and sponges without loss of RTP properties. This work demonstrates a sustainable strategy for constructing RTP materials using biomass-derived cellulose as a structural scaffold, offering a promising pathway for high-value utilization of agricultural waste in anti-counterfeiting and information encryption.
Biomass is an abundant renewable carbon resource for the sustainable production of fuels and value-added chemicals. Electrocatalytic hydrogenation (ECH) provides a mild and attractive route for upgrading biomass-derived molecules without the need for externally supplied high-pressure H2. However, the structural complexity and multifunctionality of biomass substrates give rise to intricate reaction networks, while the competing hydrogen evolution reaction (HER) often limits Faradaic efficiency and product selectivity. In recent years, alloy-based catalysts have attracted increasing attention because of their outstanding hydrogenation performance in biomass electrocatalysis. This review summarizes recent progress in alloy-based catalysts for the ECH of biomass-derived molecules, covering phenolic compounds, aldehydes, and lignin-related substrates. Emphasis is placed on mechanistic understanding, including Langmuir-Hinshelwood and proton-coupled electron transfer pathways, as well as on structure-activity/selectivity relationships. Key challenges and future opportunities are also discussed from the perspectives of mechanism-guided catalyst design, electrolyte and reactor engineering, and the upgrading of complex biomass feedstocks.
The efficient recycling of polyethylene terephthalate (PET) waste is essential for sustainable development, owing to the extensive utilization of this plastic in daily life. However, the high depolymerization energy barrier inherent to conventional single thermal catalytic technology constrains its reaction efficiency, necessitating substantial external heat input and energy consumption. Recently, photothermal synergistic catalysis has emerged as one of the most promising methods for PET glycolysis regeneration, with its core lying in the photothermal conversion and catalytic mechanism. In this review, the core mechanisms and recent advances in the photothermal catalytic depolymerization of PET to bis(2-hydroxyethyl) terephthalate (BHET) are systematically discussed. First, this review elucidates the critical role of photothermal conversion in PET recycling based on the structural characteristics of PET and the thermodynamic and kinetic principles governing its depolymerization. Particular emphasis is placed on how photothermal synergistic catalysis significantly lowers the depolymerization energy barrier and enhances reaction efficiency. Subsequently, the depolymerization mechanism of PET is analyzed in detail, with a focus on the synergistic promotion by catalyst active sites of electrophilicity of carbonyl groups in PET ester bonds and the nucleophilicity of the hydroxyl oxygen in ethylene glycol (EG), thereby achieving efficient transesterification.
The pincer acetate complexes trans-[Ru(η1-OCOCH3)2(PNN)(PPh3)] (PNN = N-(2-(diphenylphosphaneyl)benzyl)-1-(pyridin-2-yl)methanamine (PNN') 1, 2-(diphenylphosphaneyl)-N-(pyridin-2-ylmethyl)ethan-1-amine (PNNG) 2) are synthesized from [Ru(η2-OCOCH3)2(PPh3)2] and the corresponding PNN ligands in acetone. Reaction of [RuH(η2-OCOCH3)(PPh3)3] with the PNN ligands in n-heptane gives trans-[RuH(η1-OCOCH3)(PNN)(PPh3)] (PNN = PNN' 3, PNNG 4). Substitution of PPh3 in 1 with PPh2Me gives trans-[Ru(η1-OAc)2(PNN')(PPh2Me)] (5) in toluene, whereas starting from 2 results in trans-[Ru(η1-OAc)2(PNNG)(PPh2Me)] (6) and cis-[Ru(η2-OAc)(PNNG)(PPh2Me)]OAc (7) (in 1:1 ratio). The monocarbonyl [Ru(η2-OAc)(CO)(PNN')]OAc (8) and cis-[Ru(η1-OAc)2(CO)(PNN')] (9) (in 3:1 ratio) are formed from [Ru(η1-OAc)(η2-OAc)(CO)(PPh3)2] with PNN', whereas reaction of the latter precursor with 1-(2-(diphenylphosphaneyl)phenyl)-N-(2-(pyridin-2-yl)ethyl)methanimine (PNN(C2)imine) affords cis-[Ru(η1-OAc)2(CO)(PNN(C2)imine)] (10). Acetate complexes 1-9 catalyze the homogeneous hydrogenation of methyl decanoate to 1-decanol with NaOMe under mild reaction conditions (T = 40 °C, H2 pressure 27.5 bar) and low catalyst loading (S/C 1000-100 000) in the absence of solvents. Complex 2 displays extremely high catalytic activity for the reduction of fatty acid methyl and ethyl esters at S/C of 50 000-100 000, with high chemoselectivity and without CC bond reduction. In addition, 1-4 and 8/9 are found to catalyze the base-free hydrogenation of aldehydes. NMR studies show that 1 reacts with H2 (5 bar), affording the monohydride 3, which, with KOtBu and hydrogen, reduces methyl benzoate to benzyl alcohol.
