ChemSusChem最新文献

The Front Cover shows a liquid hand made of molecules and ions for capturing dilute carbon dioxide from the air. The alkaline absorbing solution, consisting of sodium cations, hydroxide anions, and water molecules, is capable of effectively capturing carbon dioxide in a closed-loop and precipitation-free electrochemical process. More information can be found in the Research Article by J. Zhou and X. Guan.

The Cover Feature shows a comparative study on transforming 2,5-bis(hydroxymethyl)furan to 2,5-furandicarboxylic acid by thermal and electrocatalysis. On a cheap Co@NC catalyst, thermal catalysis crawls like a turtle, whereas electrocatalysis races like a cheetah. Moreover, employing renewable wind or solar power for electrocatalysis promises a greener future than conventional thermochemical factories. More information can be found in the Research Article by J. Zhang, C. Chen and co-workers.

Lignocellulosic biomasses have the potential to generate by-products with biological activity (i. e., polyphenols) as well as biopolymers (i. e., cellulose, hemicellulose, pectins, lignin). The wine industry is one of the pillars of Italian agri-food sector. Nevertheless, large quantities of by-products such as grape stems are produced, which are usually disposed of at a cost, and therefore represent an attractive negative-cost feedstock for biorefinery. In this work, a sequential protocol for biomass valorization is proposed, characterized by a multidisciplinary strategy using enabling technologies and subcritical water as a green solvent, where physical/chemical treatments synergistically interact with biological treatments. The first phase involved the sequential fractionation of grape stalks, obtaining several product streams rich in polyphenols, hemicellulose, pectin (13.15 % of cumulative yield on biomass), lignin and cellulose. A membrane treatment was employed to recycle materials within the process. Finally, the cellulose-rich residue was exploited as a fermentation substrate for the last step, producing up to 5.8 g/L of lactic acid by harnessing suitably engineered Clostridium thermocellum strains. The polyphenolic fraction successfully inhibited the growth of Brettanomyces bruxellensis and Acetobacter pasteurianus, microorganisms responsible for major wine off-flavors. Globally, this study represents a proof-of-concept of a second-generation biorefining process based on locally available waste biomass.

The localized surface plasmon resonance (LSPR) effect can effectively utilize and transform solar energy, which is an ideal candidate to solve the energy crisis. In particular, plasmon hot carriers generated by LSPR effect are the focus of current research because their energy characteristics are higher than the Fermi level, which can easily promote the chemical reaction on the catalysts and improve the photoelectric performance of the optoelectronic devices. In this review, the generation of hot carriers and their decay pathways under different nano-structured models are discussed, and their unique significance is highlighted. Meanwhile, recent research advances in cognizing the plasmon hot carriers, the role of hot carriers in various applications, and the regulating mechanism of hot carriers in the nanostructure are discussed in depth. In addition, the limitations and challenges of the current research on plasmon hot carriers are presented, and prospects for the future are proposed.

We here report the synthesis of two types of six-membered cyclic carbonate monomers equipped with various drug molecules through ester linkages. The target compounds can be isolated in good yields and feature diagnostic IR and ¹³C NMR spectroscopic fingerprints in line with their proposed connectivities. As a potential application, we investigated their ring-opening polymerization (ROP), showing that the nature of the cyclic carbonate is crucial towards macromolecular carbonate formation. The functionalized polycarbonates have molecular weights of up to 10 kg/mol, controllable functionality and a variable drug-to-carbonate ratio. This work demonstrates the adaptive synthesis of new types of functionalized six-membered cyclic carbonates with potential as precursors to polycarbonate-drug type macromolecules.

Zeolites are a group of crystalline aluminosilicates with exchangeable cations and molecular-dimensioned micropores, which have successfully been applied to transform biomass and waste into biofuels. Herein, the effectiveness of acidic H-zeolites in biomass transformation and chemical valorization is demonstrated. In this process, the Brønsted/Lewis acid sites in zeolites catalyze the transition of carbohydrates into valuable chemicals. β-glucan polymer extracted from the lichen Usnea was catalytically converted into value-added molecules, such as glucose monomers. Particular challenges to elucidate the zeolite-catalyzed β-glucan conversion to glucose were addressed, namely: (i) water as the solvent, ii) hydrolysis of the biopolymer in an ionic liquid of 1-Butyl-3-vinylimidazolium bromide ([BVinIm]Br), and iii) reaction time of 30, 60, 120, and 240 min. Effective hydrolysis of β-glucan was achieved by H-zeolites (H-Beta, H-Mordenite, and H-ZSM-5), and the formed glucose was quantified through the dinitrosalicylic acid (DNS) method. Finally, applying H-zeolites as heterogeneous catalysts to prove the chemical recyclability of flexible films based on β-glucan was demonstrated as a step forward in integrating biopolymer-based materials into the circular economy.

N,N-dimethylformamide (DMF) and trifluoroacetic acid (TFA) are the two solvents/reagents most widely used in solid-phase peptide synthesis (SPPS). While DMF is already regulated in Europe, TFA - a member of the polyfluoroalkyl substances (PFAS) family - is expected to face similar restrictions soon. These compounds break down slowly and pose risks to human health and the environment. Herein, the use of the so-called "green acid par excellence", methanesulfonic acid (MSA), in substitution of TFA is discussed. As MSA is stronger than TFA, it is diluted with a solvent for use. The effectivity of MSA depends on the solvents used. When dichloromethane (DCM) is used, 1.5 % MSA removes all side-chain protecting groups, except the trityl (Trt) group of His. In the presence of acetic acid (AcOH) and dimethylcarbonate (DMC), more concentrated solutions of MSA (8-16 %) are required. The removal of the Trt group of Asn/Gln continues to be a challenge even with these solutions, and aspartimide formation can occur in Asp-containing peptides.

The abatement of aromatic pollutants in water requires their oxidation to nontoxic products by resource-intensive reactions with hydroxyl radicals (•OH). We elucidate the mechanisms of •OH-induced aromatic ring degradation by combining kinetic measurements, electron paramagnetic resonance spectroscopy, density functional theory calculations, and kinetic modelling. We demonstrate that benzyl alcohol, a model aromatic compound, is oxidized by •OH radicals, generated by ultrasonic irradiation in an O2-rich environment, into aromatic compounds (benzaldehyde and phenol derivatives) and C1-C2 oxygenates (formic acid, glyoxal, and oxalic acid). Through pathways akin to atmospheric chemistry, these •OH radicals de-aromatize and fragment benzyl alcohol, producing 5-hydroxy-4-oxo-pentenal and other dicarbonyl products. Unique to the aqueous phase, however, superoxide (•O2-) forms by •OOH deprotonation, which is generated by ultrasound (alongside •OH) and as a byproduct of •OH-benzyl alcohol reactions. •O2- acts as a nucleophile, oxidizing 5-hydroxy-4-oxo-pentenal into oxalic acid and C1 oxygenates via aldehyde and ketone intermediates. This process regenerates •O2- and does not consume •OH, thereby further degrading ring fragmentation products while preserving •OH to activate the refractory aromatic ring of benzyl alcohol. These nucleophilic •O2-reactions can therefore reduce the energy and number of chemical initiators needed to degrade aromatic compounds, thus advancing •OH-based oxidation processes in water treatment.

Redox-active covalent organic frameworks (COFs) with metal binding sites are increasingly recognized for developing cost-effective, eco-friendly organic electrodes in rechargeable energy storage devices. Here, we report a microwave-assisted synthesis and characterization of a triazine-based polyimide COF that features dual redox-active sites (-C=O from pyromellitic and -C=N- from triazine) and COF@CNT nanocomposites (COF@CNT-X, where X=10, 30, and 50 wt % of NH₂-MWCNT) formed through covalent linking with amino-functionalized multiwalled carbon nanotubes. These composites are evaluated as cathode materials for the sodium-ion batteries (SIBs). The amine functionalization renders the covalent bond between COF and CNT, improving electronic conductivity, structural rigidity, and long-term stability. The interfacial growth of COF layers on CNTs increases accessible redox-active sites, enhancing sodium diffusion kinetics during sodiation/desodiation. The COF@CNT-50 composite exhibits outstanding Na⁺ ion storage performance (reversible capacity of 164.3 mAh g^-1 at 25 mA g^-1) and excellent stability over 1000 cycles at ambient temperature. At elevated temperature (65 °C), it also maintains good capacity and cycle stability. Ex situ XPS analysis confirms the importance of dual active sites in the Na⁺ diffusion mechanism. Density functional theory (DFT) calculations reveal insights into Na⁺ binding sites and corresponding binding energies into COF structure, elucidating the experimental storage capacity and voltage profile.

A donor-acceptor-donor (D-A-D) molecule, denoted as RC18, consisting of two nickel-porphyrin terminal donor units (D) and a selenophene-flanked diketopyrrolopyrrole central core, connected via an ethynylene linker has been synthesized. The highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels were measured showing values of -5.49 eV and -3.75 eV, respectively. We have utilized RC18 as donor along with two acceptors, DICTF and Y6, for OSCs and found that power conversion efficiencies were 12.10 % and 12.59 % for RC18:DICTF and RC18:Y6, respectively. The complementary absorption profiles of RC18, DICTF and Y6, along with the intermediate LUMO level of DICTF between RC18 and Y6, led to the fabrication of ternary organic solar cells. RC18:DICTF:Y6 based ternary attained power conversion efficiency of 16.06 %. The observed enhancement in the PCE is attributed to efficient exciton utilization through energy transfer from DICTF to Y6, increased donor-acceptor interfacial area, suppressed charge carrier recombination and improved molecular ordering. These all factors contribute to improvements in short-circuit current density (J_SC) and fill factor (FF). Additionally, the open-circuit voltage (V_OC) of the ternary OSC lies between those of the two binary OSCs indicating the formation of an alloy between the two acceptors.