ChemSusChem最新文献

Conventional metal–zeolite catalysts often face diffusion limitations in hydrocracking polyolefin wastes due to the poor accessibility of active sites within zeolitic micropores. In this study, commercial BEA zeolite was modified through various post-synthetic treatments, followed by nickel loading via incipient wetness impregnation, to enhance both structural and acidic properties. Among them, the TEAOH-assisted hydrothermal modification (Ni/BEA-TEA) generated a hierarchical architecture with optimized Al distribution, strengthening surface acidity while preserving crystallinity. This catalyst achieved 84.5% polyethylene (PE) conversion with 89.5% selectivity toward gasoline–diesel-range hydrocarbons at 280°C. The remarkable activity enhancement is attributed to improved acid site accessibility and balanced hydrogenation–cracking synergy. This work highlights that tailoring acid-site distribution and surface structure through controlled zeolite modification provides an effective strategy for designing advanced bifunctional catalysts for efficient and selective polyolefin upcycling.

The development of high-performance, noble-metal-free photocatalysts for the hydrogen evolution reaction (HER) is meaningful for sustainable development. While it remains a significant challenge. Herein, a novel covalent organic framework (COF), named BN-COF, was designed by the imine condensation between the (N4, N4-bis(4′-amino-[1,1′-biphenyl]-4-yl)-[1,1′-biphenyl]−4,4′-diamine) (NBD/N) and benzo[1,2-b:3,4-b′: 5,6-b″]trithiophene-2,5,8-tricarbaldehyde (BTT/B) monomers, as electron donor and acceptor, respectively. The BN-COF is synthesized facilely via a liquid–liquid interfacial (LLI) strategy. The BN-COF shows photocatalytic HER activity of 7.8 mmol g⁻¹ h⁻¹ under AM 1.5 G irradiation without any cocatalysts and maintains the activity over 5 recycling reactions. This remarkable activity stems from the enhanced charge separation, driven by a stronger built-in electric field within the donor-acceptor structure, coupled with enhanced hydrophilicity imparted by the thiophene group. This work highlights the significant potential of rationally engineered D-A structure and LLI synthetic strategy for developing effective noble-metal cocatalyst-free photocatalysts for efficient solar-to-chemical energy conversion.

Conductive hydrogels are crucial to intelligent robotics and wearable devices, but their adoption is hindered by limited functionality and energy-intensive petrochemical synthesis. To address this challenge, a nanolignins (NLs)-reinforced polyacrylamide hydrogel (NL@PAM) was prepared via a green strategy at room temperature. Lignin nanoparticles were synthesized by a green method and integrated into the polyacrylamide network through extensive hydrogen bonding and interchain interactions. This structure imparts the NL@PAM hydrogel with a unique combination of mechanical and functional properties, including high tensile strength (1.32 MPa), ultrahigh stretchability (1880%), strong self-adhesion (196 kPa), and high ionic conductivity (13.96 mS cm⁻¹). As a demonstration, the hydrogel was used as a wearable sensor on human fingers; it converted real-time finger movements into control signals for a robotic arm, which faithfully replicated the gestures. These results demonstrate a high-performance multifunctional hydrogel and establish a sustainable paradigm for soft electronics, leveraging green chemistry and renewable biomass for future intelligent systems.

Mechanochemistry in planetary ball mills is a transformative and sustainable chemical process by which mechanical impact is converted into reaction-driving energy. High-energy collisions between balls, analogous to meteorite impacts on Earth, generate transient extreme pressures (∼10 GPa) and temperatures (∼1500°C) and supercritical water in microscale “hot spots,” allowing reactions once restricted to high-temperature or solvent-intensive laboratory or industrial conditions to proceed. This platform achieves hydrogen evolution efficiencies comparable or superior to electrolysis and even realizes a new phenomenon—room-temperature thermochemical water-splitting cycles—without CO₂ emissions, oxygen separation systems, or external heaters. Furthermore, the mechanochemical activation of TiO₂ yields photocatalysts with markedly enhanced absorption from the UV to the near-infrared through defect and polymorph engineering. Beyond energy applications, the direct halogen-free, HF-free synthesis of alkoxysilanes provides a green, scalable route to value-added chemicals with the coproduction of hydrogen at room temperature. These processes exploit abundant or waste materials, operate in compact setups, and consume very little energy, suggesting their potential for distributed fuel generation and sustainable materials manufacturing. Planetary ball milling can therefore offer a generalizable framework for green chemistry, bridging solid-state reaction engineering with energy conversion and functional materials synthesis to provide practical routes toward low-carbon, scalable technologies.

Sodium-ion batteries (SIBs) have emerged as promising alternatives to lithium-ion batteries for large-scale energy storage systems, but their development is hindered by the lack of high-performance cathode materials. Na₃V₂(PO₄)₃ (NVP), with a NASICON structure, is a potential cathode candidate; however, its insufficient structural stability and sluggish Na⁺ diffusion kinetics limit its practical applications. Herein, a low-entropy doping strategy is proposed to modify NVP by incorporating multimetal ions (Ti, Cr, Fe, Mn, and Ca) to obtain low-entropy NVP-based materials (NV_2−xM_xP) via a sol–gel method followed by annealing. The optimized NV_1.8M_0.2P delivers a discharge capacity of 97.09 mAh g⁻¹ at 0.5 C, retains 59.19 mAh g⁻¹ at 20 C (60.97% capacity retention), maintains 91.76% capacity after 200 cycles at 1 C, and still retains 85.01% of its initial capacity after 4000 cycles at 10 C. X-ray diffraction (XRD) Rietveld refinement results reveal that low-entropy doping induces unit cell contraction of NV_2−xM_xP, thereby enhancing its structural stability. Partial density of states (PDOS) calculations indicate that this doping strategy reduces the bandgap of NVP from 1.32 to 0.173 eV, significantly enhancing electronic conductivity. Electrochemical impedance spectroscopy and galvanostatic intermittent titration technique reveal that NV_1.8M_0.2P exhibits a lower charge transfer resistance (449.2 Ω) and a significantly higher Na⁺ diffusion coefficient (3.8 × 10⁻⁶ cm² s⁻¹) compared to pristine NVP (8.3 × 10⁻⁸ cm² s⁻¹). Furthermore, ex situ XRD and X-ray photoelectron spectroscopy verify the reversible structural transformation of NV_1.8M_0.2P and the V³⁺ ↔ V⁴⁺ redox reaction during cycling. This low-entropy doping strategy not only provides an effective approach for optimizing NVP-based cathodes but also offers a valuable guideline for designing advanced electrode materials for high-performance SIBs.

The valorization of biomass into renewable, high-performance, adsorbent materials offers a sustainable alternative to conventional synthetic sorbents. In this study, we investigate the potential of lignin derivatives as efficient adsorbents for removing the cationic dye Rhodamine B (RhB) from aqueous solutions. Five organosolv lignin derivatives were synthesized via a one-step process using phenol, catechol, resorcinol, pyrogallol, and hydroquinone as phenolic modifiers to introduce structural diversity. The influence of these modifications on the materials’ physicochemical properties and adsorption behavior was examined. Comprehensive characterization included ³¹P NMR, Brunauer–Emmet–Teller surface area analysis, size exclusion chromatography, thermogravimetric analysis, and dynamic light scattering. Among the derivatives, resorcinol-modified lignin (ReL) showed the highest RhB adsorption capacity (101.2 mg g⁻¹), attributed to its favorable textural properties—high surface area and pore volume—together with increased availability of functional groups, which collectively enhanced adsorption efficiency. Adsorption kinetics for all materials followed the pseudo-second-order model, indicating chemisorption as the dominant mechanism. Isotherm analyses revealed Langmuir-type monolayer adsorption for ReL, pyrogallol-modified, and hydroquinone-modified lignins. Moreover, ReL demonstrated good recyclability, retaining 62% of its adsorption efficiency after five adsorption–desorption cycles. Collectively, these results highlight the promise of structurally engineered lignin-based adsorbents as cost-effective, efficient, and reusable materials for sustainable wastewater treatment.

Metaraminol is a chiral amino alcohol and plays an important role as a precursor molecule and active pharmaceutical ingredient in industry. Its enzymatic synthesis has been developed in recent years and can serve as an alternative to conventional synthesis routes that use toxic, fossil-based resources. Although the enzymatic two-step reaction toward metaraminol has been intensively investigated in the past, full conversion has never been reached in the amine transaminase-catalyzed step. In this study, we focus on identifying and overcoming the hurdles of the transamination step to reach higher metaraminol yields. Photometric and LC-MS analyses revealed side-product formation as a major drawback for the enzymatic metaraminol synthesis. Besides the oxidation of (R)-3-OH-PAC as well as its imine formation with isopropylamine, we demonstrate for the first time the adduct formation of the cofactor pyridoxal-5’-phosphate with metaraminol. Only by changing the amine transaminase formulation to purified enzyme and increasing the concentration by tenfold, >99% product yield with a metaraminol concentration of 75 mM was reached. Further, we successfully integrated the amine donor l-alanine by applying a continuous product extraction system as an alternative to isopropylamine. We believe that our findings and optimization strategies can also serve as a blueprint for other amine-based syntheses.

Hydrogen is expected to be used as a fuel additive to ammonia, a non-flammable and carbon-free fuel, to improve combustion efficiency. However, the design strategies for developing highly active, nonprecious metal catalysts for ammonia decomposition are not yet well understood. Here, we show that Co/Ba_0.01Mg_0.99O exhibits high activity, with an ammonia conversion of 94.4% and a hydrogen production rate of 3.79 mol g_cat⁻¹ h⁻¹ at 500°C with a WHSV of 60,000 mL g_cat⁻¹ h⁻¹. Comparison of the dopant effects of alkaline earth metal elements elucidates that the high activity of Co/Ba_0.01Mg_0.99O is ascribed to the formation of a specific Co-BaO core–shell-like structure, with highly basic BaO nanoparticles covering the Co particles. The core–shell-like structures were not formed with other alkaline earth elements. Such features facilitate efficient electron donation to Co nanoparticles, promoting N₂ formation. Furthermore, kinetic analysis indicated that doping of alkaline earth metals weakens the adsorption of strongly bound species. Our findings will contribute to the development of cost-effective supported metal catalysts for hydrogen production through ammonia decomposition, leading to the realization of a carbon-neutral society in which ammonia plays a key role.

Condensation polymers are extensively utilized across various industries, including applications in bottles, fibers, films, and engineering materials. As an industrial fundamental method for the synthesis of condensation polymers, the polycondensation process has undergone significant development over the past century. A defining feature of polycondensation is the occurrence of exchange reactions, which are critically important in both polymer synthesis and recycling processes, such as alcohol-ester and acid-alcohol exchange reactions. This review provides an in-depth discussion of exchange reactions, highlighting several representative examples applied in polymer synthesis and recycling. It further explores the underlying reaction mechanisms and reviews relevant studies on polymer synthesis using this polycondensation approach. In light of the persistent challenge posed by plastic pollution, this article also discusses the role of exchange reactions in polymer recycling, with the objective of offering meaningful insights into the sustainable reuse of condensation polymers. Furthermore, the review identifies current limitations of the polycondensation technique and discusses potential directions for future research and development.

The mechanochemical depolymerization of commercial PET feedstocks is successfully demonstrated for a variety of samples representing consumer products without the need for specific sample pretreatment. Complete depolymerization is achieved within 20 min by ball milling it with NaOH under ambient conditions. Samples with a higher initial content of amorphous domains depolymerize more rapidly, as collision energy is more effectively utilized for creating reactive interfaces between NaOH and PET. While thickness has a minor effect compared to crystallinity, thicker samples experience lower reaction rates because their accessible surface area is limited. For low-packing density samples, a reduced rate of depolymerization could be expected due to restricted ball motion, but this effect is overcompensated by the ease at which these samples form interfaces. The success of mechanochemical alkali-depolymerization of PET in a ball mill presents an opportunity for industrial implementation, offering a sustainable approach to polymer upcycling due to its mild reaction conditions and minimal solvent requirements.