Green Chemistry最新文献

A novel photocatalytic acylation strategy was developed harnessing tetrabutylammonium decatungstate (TBADT) as a hydrogen atom transfer (HAT) photocatalyst to facilitate the direct coupling of aldehydes with N-heterocycles at ambient temperature. This approach realizes the direct acylation of N-hetrerocycles without the need for noble metals, acids, or external oxidants, thereby marking a significant advance in green chemistry protocols. Utilizing this photocatalyzed method, we successfully synthesized a diverse array of 3-acylated azauracils and quinoxalin-2(1H)-ones, adorned with a variety of functional groups, achieving yields ranging from good to excellent. This research opens avenues for the rapid and efficient modification of heterocyclic compounds, which are foundational structures in medicinal chemistry and materials science.

The production of jet-fuel precursors from furfural via aldol-condensation with methyl-isobutyl ketone (MIBK) over defect-engineered UiO-66(Zr) catalysts is presented. The catalysts are prepared using formic acid (FA), trifluoroacetic acid (TFA) and HCl as synthesis modulators, leading to the incorporation of defects on the microcrystalline structure of the metalorganic framework (MOF) material, which dramatically boosts the catalytic performance. An extensive characterization of the modified catalysts by means of X-ray diffraction (XRD), argon adsorption isotherm, thermogravimetry (TGA), transmission electron microscopy, and FTIR spectroscopy of adsorbed acetonitrile, confirmed the incorporation of missing-linker and missing-node defects within the MOF structure, enabling the explanation of the enhancement in the catalytic process. The analysis of the reaction kinetics evidences that, working under moderate temperature conditions, conversion of furfural and selectivity to the desired adduct (FuMe) close to 100% can be achieved, avoiding the formation of degradation and bulkier compounds. Finally, despite the generation of defects within the UiO-66(Zr) structure, the resultant catalyst displays good reusability in low furfural concentration mediums.

How to efficiently deal with waste acids and bases produced by industry has constantly been a tough question for scientists and engineers. Such acid–base wastewaters are normally treated by mixing to give neutral products (i.e., water and salts) and heat which is hard to collect and reuse. Therefore, there is a need for innovative approaches with high efficiencies and high-value added products. Here, we report an air/metal hydride battery with the function of both treating acid–base wastewaters and gathering the waste heat energy in the form of electricity. Remarkably, the proposed battery could exhibit a high coulombic efficiency of up to ca. 94%, along with an effective reduction in the acidity/alkalinity of waste acids/bases and a decent amount of electricity. The proposed battery device also demonstrates a stable operation in semi-flow mode over a two-day timescale, showcasing its potential scalability and long-term stability. Moreover, life cycle assessment results indicate that electricity retrieved from the treatment process is a key contributor to reducing environmental impacts. This work offers alternative opportunities for accelerating the transition to a waste acid–base circular economy.

We demonstrate that transketolase variants from Geobacillus stearothermophilus catalyse an acyloin condensation reaction involving two hydroxylated or not aliphatic aldehydes. This promiscuous TK-catalysed reaction offers an attractive alternative to the ketol transfer from α-ketoacids used as donor substrates in the usual TK mechanism, adding atom economy by avoiding carbon dioxide release. Transketolase variants H102L/L118I/H474G(S) showed a de novo activity towards the self-condensation of propanal, and to a lesser extent of ethanal, and a remarkable ability to control the selectivity of the more challenging cross-acyloin condensation reaction with propanal or iso-butanal used as nucleophiles, and different hydroxylated aldehydes (C2–C4) as electrophiles. The synthesis of seven aliphatic symmetrical and unsymmetrical α-hydroxyketones was performed from stoichiometric amounts of aldehydes, giving yields similar to those obtained with the common TK reaction based on α-ketoacid decarboxylation. This novel enzymatic cross-acyloin condensation reaction extends the toolbox for the synthesis of unsymmetrical aliphatic α-hydroxyketones while improving mass metrics of previous enzymatic and chemical strategies.

The world is committed to reducing CO₂ emissions, and research on CO₂ capture and effective utilization is being actively studied. Among the methods in development, direct air capture (DAC) is classified as a negative emission technology and has attracted significant study. The current problem with CO₂ capture technologies for decarbonization is their cost due to the high separation energy required to release CO₂. We have developed a new light-swing method that can potentially utilize a natural source of energy, i.e., sunlight, as an alternative to temperature- and pressure-swing methods. Herein, we report photoirradiation-based CO₂ capture based on photoisomerization of azobenzene-amine and guanidine derivatives. The visible light-swing CO₂ absorption and release system using azobenzene-guanidine has shown potential in DAC systems owing to its reusability. A plausible mechanism for CO₂ release under light irradiation involves photoisomerization from trans- to cis-azobenzene in which steric repulsion with other molecules is the driving force, and CO₂ is released due to the functional disruption of intermolecular interactions. This concept demonstrates the potential of using various photokinetic molecules as a driving force for light-swing CO₂ capture.

To replace depleting freshwater resources, seawater, with its abundance and economy, has become a more favourable option for water electrolysis. However, seawater electrolysis necessitates electrocatalysts with excellent activity as well as resistance to Cl⁻ corrosion. Herein, we utilized a biowaste, eggshell membranes, as a versatile platform to fabricate sulfide electrocatalysts for the oxygen revolution reaction (OER). Structural analyses including X-ray diffraction, X-ray photoelectron spectroscopy and Raman spectroscopy tests indicated that the introduction of iron into the cobalt sulfide lattice greatly modified the structures of the sulfide. Electrochemical tests and operando electrochemical Raman spectroscopy showed that the introduction of Fe adjusted the electronic structure of Co₉S₈, facilitating the formation of Co⁴⁺ species, which serve as the major active sites for OER, thereby effectively improving the catalyst performance. The optimal Co₈FeS₈/ESM-900 sample can achieve a current density of 10 mA cm⁻² in alkaline freshwater, simulated seawater, and natural seawater at overpotentials of 270, 271, and 324 mV, respectively, which are lower than the overpotentials of 273, 272, and 337 mV obtained from IrO₂. The sulphate passivation layer formed during the OER process can effectively repel Cl⁻, leading to outstanding corrosion resistance. The Co₈FeS₈/ESM-900 catalyst can be continuously operated in seawater electrolysis for 200 000 s. A (−)Pt/C||Co₈FeS₈/ESM-900(+) electrolyzer required only 1.629, 1.623, and 1.648 V to yield a current density of 10 mA cm⁻² for the electrolysis of alkaline freshwater, simulated seawater, and natural seawater, respectively, which are superior to the performance of the (−)Pt/C||IrO₂(+) electrolyzer. In virtue of its low cost, high efficiency and outstanding stability, the catalyst reported in this study is promising in practical seawater electrolysis.

Deep eutectic solvents (DESs) have been widely applied to recover spent lithium-ion batteries (LIBs); however, developing effective and efficient systems for cathode leaching via the traditional trial-and-error method requires substantial efforts. This work aims to accelerate the discovery of novel promising DESs by leveraging the conditional Generative Adversarial Network (CGAN). Three databases were constructed: (i) DESs leaching cathodes, (ii) DESs leaching metal oxides, and (iii) DES properties. The absolute Spearman's rank correlation and agglomerative hierarchical clustering analysis ensured the selection of an optimal feature set for building predictive models. An XGBoost model was developed, achieving remarkable performance (R² = 0.9702, MSE = 0.0007) in predicting cathode solubility in DESs. We employed the Shapley additive explanation (SHAP) method to quantify the importance of acidity, coordination, and reducibility of DESs and provide insights into further research. To accelerate time-consuming investigational procedures, a CGAN model was established, rapidly identifying promising DESs like ChCl : Glycolic acid, with excellent agreement between predictions and experimental results. This study offers a general data analysis framework for other metal oxides (e.g., Cu_xO, Fe_xO_y, ZnO) leaching using DESs, enabling accurate solubility prediction and deepening the understanding of cathode leaching mechanisms. The CGAN model significantly accelerates the development of a DES-based process for lithium-ion cathode recycling, saving development time and effort. Overall, this work facilitates the efficient discovery and development of effective DESs for the recovery of valuable metals from spent LIB cathodes.

The past decades have witnessed the rapid development of lithium-ion batteries (LIBs), which are applied in nearly every aspect of our daily life. However, the increasing number of spent LIBs (S-LIBs) poses a great threat to the environment. Thus, to protect the environment and preserve limited lithium resources, it is necessary to recycle S-LIBs. In this review, we initially provide a brief introduction on the structure and degradation mechanism of LIBs and pretreatment of S-LIBs. Subsequently, we highlight the recent advancements in the development of recycling the cathode of S-LIBs, including its direct, hydrometallurgical, and pyrometallurgical recovery. The advantages and disadvantages of each recycling process are also discussed from the viewpoint of the environment and economy. In addition, we also introduce the recycling of S-LIBs through a green and environmentally friendly process of treating waste with waste. Finally, the overall perspective of this technology and areas requiring particular attention in the future are discussed.

Cesium lead halide (CsPbX₃) perovskite quantum dots (PQDs) have attracted attention for use as absorber materials in photovoltaics as they show tuneable bandgap energy and high photoluminescence quantum yields together with the potential to demonstrate long-term stability and simple solution processability. Currently, the colloidal synthesis of PQDs relies to a large extent on the use of toxic and fossil derived solvents as the reaction medium. Alternative methods that partially or completely replace such solvents are anticipated as a step forward in meeting the sustainability criteria for the large-scale synthesis of PQDs. Herein, we report an eco-friendly sonochemical-assisted synthesis of CsPbBr₃ PQDs using commercial vegetable oil solvents as the reaction medium. The effect of different vegetable oils on the synthesis and properties of PQDs was investigated in detail. The as-prepared CsPbBr₃ colloids show similar photoluminescence (PL) spectra and crystalline structure to colloids obtained in mineral oil, which was used here for comparative purposes. Furthermore, a smaller amount of the optically inactive Cs₄PbBr₆ hexagonal crystalline phase was detected in the green synthesis compared to mineral oil-based synthesis. Finally, spin-coated thin films were produced, demonstrating the processability of the colloidal PQDs obtained via the green synthesis described here.