RSC Advances最新文献

The synthesis of gold nanoparticles (AuNPs) via green methods is advantageous due to their economic viability, reduced environmental pollution, and safety towards human health. According to our best knowledge, there is limited documented research on synthesizing AuNPs using gum Arabic (GA) and cinnamon (CNM) and studying their anticancer activities against colorectal cancer cells. This study presents a simple approach to synthesizing AuNPs using GA and CNM, characterized by advanced analytical techniques, including UV-Vis and FTIR spectroscopies, SEM, EDS, TEM, SAED, Zeta sizer, and Zeta potential. The absorption spectra displayed characteristic bands between 520–530 nm, confirming the successful synthesis of AuNPs. TEM analysis revealed that AuNPs@GA exhibited a spherical shape, while AuNPs@CNM displayed diverse morphologies (e.g., spherical, hexagonal, and diamond shapes) with average sizes of approximately 12 nm and 17 nm, respectively. SEM/EDS data confirmed the presence of AuNPs alongside organic compounds such as carbon, oxygen, and phosphorus. The cytotoxic effects of these AuNPs were evaluated on colorectal cancer cells (HCT-116) and healthy cells (HEK-293) using an MTT assay. Notably, AuNPs@GA resulted in a 43.61% loss in cell viability at the dose of 5 μg mL⁻¹, while AuNPs@CNM led to an impressive 80.33% loss. The calculated IC₅₀ values were 9.14 μg mL⁻¹ for AuNPs@GA and 11.76 μg mL⁻¹ for AuNPs@CNM, highlighting the potential of these AuNPs as effective agents in colon cancer treatment. This study not only addresses the lack of research on GA and CNM in NP synthesis but also demonstrates their promising anticancer properties, paving the way for further exploration in cancer therapeutics.

Lithium–sulfur batteries (LSBs) with metal lithium as the anode and elemental sulfur as the cathode active materials have attracted extensive attention due to their high theoretical specific capacity (1675 mA h g⁻¹), high theoretical energy density (2600 W h kg⁻¹), low cost, and environmental friendliness. However, the discharge intermediate lithium polysulfide undergoes a shuttle side reaction between the two electrodes, resulting in low utilization of the active substances. This limits the capacity and cycle life of LSBs and further delays their commercial development. However, the number of active sites and electron transport capacity of such catalysts still do not meet the practical development needs of lithium–sulfur batteries. In view of these issues, this paper focuses on a zinc–cobalt compound catalyst, modifying it through heteroatom doping, bimetallic synergistic effect and heterogeneous structure design to enhance the performance of LSBs as a separator modification material. A carbon shell-supported boron-doped ZnS/CoS₂ heterojunction catalytic material (B–ZnS/CoS₂@CS) was prepared, and its performance in lithium–sulfur batteries was evaluated. A carbon substrate (CS) was prepared by pyrolysis of sodium citrate, and the boron-doped ZnS/CoS₂ heterojunction catalyst was formed on the CS using a one-step solvothermal method. The unique heterogeneous interface provides numerous active sites for the adsorption and catalysis of polysulfides. The uniformly doped, electron-deficient boron further enhances the Lewis acidity of the ZnS/CoS₂ heterojunction, while also regulating electron transport. The B–ZnS/CoS₂@CS catalyst effectively inhibits the diffusion of LiPS anions by utilizing additional lone-pair electrons. The lithium–sulfur battery using the catalyst-modified separator achieves a high specific capacity of 1241 mA h g⁻¹ at a current density of 0.2C and retains a specific capacity of 384.2 mA h g⁻¹ at 6.0C. In summary, B–ZnS/CoS₂@CS heterojunction catalysts were prepared through boron doping modification. They can promote the conversion of polysulfides and effectively inhibit the shuttle effect. The findings provide valuable insights for the future modification and preparation of lithium–sulfur battery catalysts.

Fungal metabolites are known for their broad therapeutic effects. In this context, the fungal strain of Aspergillus ficuum (FCBP-DNA-1266) was examined for its secondary metabolites and in vivo activities. This led to the isolation of naphtho-gamma-pyrone (aurasperone B) and a sterol (ergosterol), characterized using advanced spectroscopic techniques such as ¹H NMR and ¹³C NMR. The isolated metabolites were evaluated for their in vivo anti-inflammatory and analgesic activities utilizing an animal model. The study showed that both metabolites have significant pharmacological effects (P ≤ 0.05) in a dose-dependent manner. In addition, in silico analysis was employed to aid the in vivo anti-inflammatory activity and the molecular docking results were in agreement with the experimental findings. For the first time, we present the pharmacological activities and 2D NMR of aurasperone B, which will shed light on the bioactive potential of secondary metabolites of Aspergillus ficuum.

Issues such as the polysulfide shuttle effect and sulfur loss challenge the development of high-energy-density lithium–sulfur batteries. To address these limitations, a tailored approach is introduced using nickel phosphide carbon composite nanofibers (Ni_xP/C) with controlled surface oxidation layers. These nanofibers feature a hierarchical structure that leverages the benefits of nickel phosphide nanoparticles and a carbonaceous matrix to enable efficient sulfur encapsulation and suppress polysulfide diffusion. Comprehensive characterization and electrochemical testing reveal that Ni_xP/C, when employed as interlayers in a cell with a bio-waste-derived carbon-based sulfur cathode, significantly enhance electrochemical performance by increasing charge–discharge capacities and reducing charge-transfer resistance. Post-mortem analyses further show effective polysulfide trapping and conversion on the cathode side, preventing their shuttle to the anode, which results in a remarkable cycle stability of up to 200 cycles at 2C with a high discharge capacity of about 800 mA h g⁻¹. These findings confirm the potential of Ni_xP/C to improve lithium–sulfur battery technologies and demonstrate their applicability in diverse lithium–sulfur cell configurations.

We report the characteristic behaviors of the hysteresis observed in the transfer characteristics of back-gated field-effect transistors with an exfoliated MoS₂ channel under various conditions. We find that the hysteresis is strongly enhanced by temperature, environmental gas, or light irradiation. Our measurements reveal the characteristic hysteresis behaviors in a 1 atm oxygen environment, which we explain as an oxygen molecule facilitated charge acceptor on the MoS₂ surface. The decrease in the current value in the ON state of the device may indicate that oxygen molecules are more effective charge acceptors than nitrogen molecules. We conclude that intrinsic defects in MoS₂, such as S vacancies, which result in effective adsorbate trapping, play an important role in the hysteresis behavior, in addition to oxygen and nitrogen adsorbates on the passivated device surface. The availability of thermally or photo-generated minority carriers (holes) in MoS₂ is increased by both light and temperature. This leads to subsequent processes of positive charge trapping, which intensify the hysteresis.

Understanding the adsorption behavior of molecular hydrogen (H₂) on solid surfaces is essential for a variety of technological applications, including hydrogen storage and catalysis. We examined the adsorption of H₂ (∼2800 configurations) molecules on the surface of fullerene (C₆₀) using a combined approach of density functional theory (DFT) and molecular dynamics (MD) simulations with an improved Lennard-Jones (ILJ) potential force field. First, we determined the adsorption energies and geometries of H₂ on the C₆₀ surface using DFT calculations. Calculations of the electronic structure help elucidate underlying mechanisms administrating the adsorption process by revealing how H₂ molecules interact with the C₆₀ surface. In addition, molecular dynamics simulations were performed to examine the dynamic behavior of H₂ molecules on the C₆₀ surface. We accurately depicted the intermolecular interactions between H₂ and C₆₀, as well as the collective behavior of adsorbed H₂ molecules, using an ILJ potential force field. Our findings indicate that H₂ molecules exhibit robust physisorption on the C₆₀ surface, forming stable adsorption structures with favorable adsorption energies. Calculated adsorption energies and binding sites are useful for designing efficient hydrogen storage materials and comprehending the nature of hydrogen's interactions with carbon-based nanostructures. This research provides a comprehensive understanding of H₂ adsorption on the C₆₀ surface by combining the theoretical framework of DFT calculations with the dynamical perspective of MD simulations. The outcomes of the present research provide new insights into the fields of hydrogen storage and carbon-based nanomaterials, facilitating the development of efficient hydrogen storage systems and advancing the use of molecular hydrogen in a variety of applications.

Modified magnetic chitosan nanoparticles (EMMCS-G), used as a Fenton-like catalyst, were successfully prepared and modified with glutaraldehyde and ethylenediamine. EMMCS-G has strong magnetization, good reusability, stability, environmental friendliness, and high efficiency. In the Fenton-like system, the synergistic effect of adsorption and advanced oxidation significantly enhances the removal effect of tetracycline (TC). The optimal concentration of persulfate was found to be 20 mmol L⁻¹, and at a pH of 3, the removal efficiency of TC reached 95.6% after 6 hours. The oxidation system demonstrated excellent pH adaptability, achieving a TC removal rate of 94% within 6 hours across a pH range of 3 to 8. Hydroxyl (˙OH) and sulfate (SO₄⁻˙ ) radicals were present in the reaction system, with ˙OH playing an important role in the oxidation process of TC. The attack sites of tetracycline were identified using density functional theory (DFT), and five degradation pathways for TC were proposed based on LS-MS experiments. Finally, quantitative structure–activity relationship (QSAR) analysis was employed to assess the toxicity of the intermediates. Overall, toxicity gradually decreased, indicating that the Fenton reaction system effectively reduced the toxicity and mutagenicity of TC. This study suggests EMMCS-G as a potential catalyst for enhanced Fenton-like degradation with excellent efficiency observed for the degradation of tetracycline for environmental remediation.

In this study, we report a novel and efficient method for the regioselective bromination of pyrrolo[1,2-a]quinoxalines using tetrabutylammonium tribromide (TBATB). This method exploits the mild nature of TBATB to obtain highly selective C3-brominated or C1, C3-dibrominated products in good yields. Notably, the reaction has a broad substrate applicability, and the C3-brominated product can be synthesized on a gram scale and can be further converted into structurally diverse pyrrolo[1,2-a]quinoxaline derivatives.

The deployment of magnetically responsive and polymeric materials to remove dyes that are hazardous in aquatic environments has profoundly revolutionized environmental sustainability. This study focuses on removing the hazardous cationic Malachite Green (MG) dye from solutions, employing a novel magnetic composite film as an adsorbent, designated as Ag_0.2Co_0.8 Fe₂O₄ (ACFCeP). The composite was synthesized via solvent casting, incorporating Ag_0.2Co_0.8 Fe₂O₄ nanoparticles and CeO₂ into a cellulose acetate/polyvinylpyrrolidone (CA/PVP) polymer matrix. The Ag_0.2Co_0.8Fe₂O₄ nanoparticles were synthesized by a co-precipitation method. Comprehensive characterization of the synthesized composite was conducted using techniques, such as Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM), and vibrating sample magnetometer (VSM). The Ag-doped cobalt ferrite component retained a strong hysteresis loop within the final composite, even when blended with the CA/PVP polymer, preserving the robust magnetic properties that facilitate the easy removal of the composite post-treatment without secondary pollution. Additionally, the mesoporous structure of the composite effectively aids in the adsorption mechanism. The isothermal study shows that both linear Langmuir isotherm and Freundlich isotherm are well fitted with R² values of 0.99 and 0.97, respectively. The linear Langmuir maximum adsorption capacity, q_max, is 45.66 mg g⁻¹ at pH 7. The kinetic studies of the composite resemble the pseudo-second-order kinetic model, reaching adsorption equilibrium within 70 min for a 100 ppm MG dye concentration. The composite film exhibits excellent reusability, maintaining high removal efficiency over three cycles. Overall, the ACFCeP composite film showcases excellent dye removal capabilities, a fast adsorption rate, and satisfactory magnetic properties and offers a sustainable solution for environmental pollution, thus contributing to ecosystem preservation through efficient recycling and reuse in dye adsorption applications.

Electrolyzing CO₂ into ethylene (C₂H₄) is a promising strategy for CO₂ utilization and carbon neutrality since C₂H₄ is an important industrial feedstock. However, selectively converting CO₂ into C₂H₄ via the CO₂ electro-reduction reaction (CO₂ ERR) is still a great challenge. Herein, Cu–Cu₂O nanoparticles anchored on reduced graphene oxide nanosheets (Cu–Cu₂O/rGO) were prepared from copper hydroxide nanostrands (CHNs) and graphene oxide (GO) nanosheets via in situ electrochemical reduction. Cu–Cu₂O nanoparticles with diameter less than 10 nm were formed on the surface of rGO nanosheets. After assembling the Cu–Cu₂O/rGO catalyst into a flow cell, it demonstrated high Faraday efficiencies (FEs) of 55.4%, 37.6%, and 6.7% for C₂H₄, C₂H₆, and H₂, respectively, and a total 93% FE for C₂ at −1.3 V vs. the standard hydrogen electrode (SHE). Moreover, its FE was 68.2% for C₂H₄, 10.2% for C₂H₆, and 20.5% for H₂ at −1.4 (vs. SHE). Besides, no liquid carbon product was detected. This high selectivity is attributed to the synergistic effect arising from the small diameter of Cu–Cu₂O NPs with the combination of Cu⁰–Cu⁺ and rGO nanosheets, which promotes the activation of CO₂ molecules, facilitates C–C coupling, and enhances stability. This may provide a facile way for designing an efficient catalyst for selectively electrolyzing CO₂ into valuable C₂ chemicals.