ACS Omega最新文献

CeO₂ (ceria) is an attractive material for heterogeneous catalysis applications involving hydrogen due to its favorable redox activity combined with its relative impermeability to hydrogen ions and molecules. However, to date, many bulk ceria/hydrogen properties remain unresolved in part due to a scarcity of experimental data combined with quantum calculation results that vary according to the approach used. In this regard, we have conducted a series of density functional theory (DFT) calculations utilizing generalized gradient (GGA), metaGGA, and hybrid functionals as well as several corrections for electronic correlations, applied to a number of properties regarding hydrogen in bulk stoichiometric CeO₂. Our calculations place reasonable bounds on the lattice constants, band gaps, hydrogen absorption energies, and O–H bond vibrational frequencies that can be determined by DFT. In addition, our results indicate that the activation energy barriers for hydrogen bulk diffusion are uniformly low (<0.15 eV) for the calculation parameters probed here and that, in general, the effect of hydrogen tunneling is small at ambient temperatures. Our study provides a recipe to determine fundamental physical chemical properties of Ce–O–H interactions while also determining realistic ranges for diffusion kinetics. This can facilitate the determination of future coarse-grained models that will be able to guide and elucidate experimental efforts in this area.

Nuclear energy is a promising low-carbon energy candidate to meet the increased demand for green energy, where the integration of fuel recycling can have significant benefits for material usage and waste reduction. Utilizing in situ monitoring tools can provide ample opportunities to better control and safeguard nuclear material recycle processes while also offering knowledge and insight into real-time solution properties. The simultaneous measurement of analytical targets in multiple process locations can enable real-time mass balance and material accountancy calculations. This is demonstrated here with a mass balance study of Nd³⁺ on countercurrent aqueous/organic metal extraction within a single centrifugal contactor. The Nd³⁺ concentration was simultaneously monitored at the inlets and outlets of both aqueous and organic phases using a visible absorbance detector that allowed for the simultaneous measurement of up to six locations. The Nd³⁺ concentration was calculated by using chemical data science algorithms, where model training sets were collected on a single track of the detector. The discussion includes addressing the challenges of using a model collected on a single track and applying it as a model across the other tracks on the detector. Each track of the detector corresponds to one measurement location on the contactor. The difference in the integrated moles of Nd³⁺ between the inlet and outlet at the end of the experiment was near zero, indicating that the mass balance of this experiment was maintained. Overall, the online spectroscopic monitoring was able to follow changing solution conditions and accurately measure the concentration of Nd³⁺ in different locations within the contactor system.

Five pyrazole-based compounds, 3,5-dimethyl-1H-pyrazole, L1; 3,5-diphenyl-1H-pyrazole, L2; 3-(trifluoromethyl)-5-phenyl-1H-pyrazole, L3; 3-(trifluoromethyl)-5-methyl-1H-pyrazole, L4; and 3,5-ditert-butyl-1H-pyrazole, L5 were synthesized from a typical condensation reaction of β-diketone derivatives with hydrazine hydrate reagent and characterized using various spectroscopic techniques such as FT-IR, UV–vis, ¹H and ¹³C NMR, and LC–MS spectroscopy. L1 was further analyzed by single-crystal X-ray diffraction, and the N1–N1′ bond distance was found to be 1.361(3) Å and correlated well with other pyrazole-based compounds. The short-term cytotoxicity of 10 μM pyrazole compounds (L1–L5) was evaluated against pancreatic (CFPAC-1 and PANC-1), breast (MDA-MB-231 and MCF-7), and cervical (CaSki and HeLa) cancer cell lines using the MTT cell viability assay. Cisplatin and gemcitabine were included as positive control drugs followed by the determination of the half-maximal effective concentrations of prospective compounds. L2 and L3, respectively, displayed moderate cytotoxicity against CFPAC-1 (61.7 ± 4.9 μM) and MCF-7 (81.48 ± 0.89 μM) cell lines.

Heavy metal ions easily accumulate in the human body through the food chain, and their binding with sulfur-containing proteins, enzymes, and various metabolites can affect the liver, kidneys, and central nervous system. The development of sensors for detecting Ag and other metal ions provides an economically efficient means of protecting the environment and human health. This review focused on the latest developments in fluorescent and colorimetric organic small-molecule sensors for identifying Ag. We analyzed their recognition principles and mechanisms; discussed their sensitivity, specificity, and stability; and conducted in-depth research on their application performance in practical environments.

This study focuses on the synthesis and characterization of Ag-embedded ZnO nanocomposites with varying silver (Ag) contents (1, 3, and 5 wt %) to evaluate their photocatalytic and antioxidant activities. The nanocomposites were synthesized using a sol–gel method, followed by thermal decomposition, and characterized by XRD, SEM, BET, Raman, EDS, TEM, FTIR, and UV–vis spectroscopy. The photocatalytic degradation of the rhodamine 6G (R6G) dye was tested under UV light, and its antioxidant capacity was evaluated using DPPH, ABTS, FRAP, and FIC assays. Among the synthesized samples, the ZnO-5 wt % Ag nanocomposite exhibited the enhanced photocatalytic efficiency, achieving 93.36% degradation of R6G, with a reaction rate constant of 6.54 × 10^–3 min^–1. It also demonstrated recyclability, retaining over 91% efficiency after five cycles. In the antioxidant assays, the ZnO-5 wt % Ag composite showed enhanced free radical scavenging capacity, confirming its strong antioxidant potential. These Ag-embedded ZnO nanocomposites offer a dual functionality, enhancing both photocatalytic and antioxidant activities. Future research will focus on their scalability and visible-light photocatalytic performance to enhance their applications in environmental remediation and biomedical applications.

Cationic cellulose stands out as a versatile and commercially important derivative of cellulose, known for its superior reactivity and functional properties. The present study demonstrates the optimal utilization and management of bagasse waste through cationic cellulose synthesis. It primarily focuses on the development of an optimized and efficient etherification strategy for cationic cellulose synthesis by systematically evaluating three distinct approaches, which could serve as a breakthrough for the selection of the best suitable media for the optimal synthesis of cationic cellulose for various industrial applications. Proximate chemical analysis was conducted to assess the chemical makeup of sugarcane bagasse, which showed the presence of 73.27% holocellulose, 23.45% lignin, 3.08% solvent (alcohol–benzene) extractives, and 5.08% ash, with an ample occurrence of alpha cellulose (43.21%), thereby showing its utility for cationic cellulose synthesis. Alpha cellulose extracted in bulk was processed through three different approaches for the preparation of cationic cellulose instead of conventional ones. Approach I removes an excess amount of water prior to etherification, while Approach II retains water from the alkalization step, and Approach III utilizes isopropanol as an additional medium during cationic cellulose synthesis. Approach I involves preparing and adding 2,3-epoxypropyltrimethylammonium chloride (EPTAC) separately, whereas Approach II forms it in situ from 3-chloro-2-hydroxypropyltrimethylammonium chloride (CHPTAC). In Approach III, EPTAC prepared separately, is added dropwise to the cellulose alkoxide. The results of the study show that the cationic cellulose synthesized by Approach I had the highest degree of substitution (0.120), followed by Approach III (0.088) and Approach II (0.016), respectively. The cationic cellulose having the maximum DS (0.12) was further characterized through Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Field Emission Gun Scanning Electron Microscopy (FEGSEM). Conclusively, heterogeneous cationic cellulose synthesis through the recommended approach (Approach I) will not only help in the preparation of a quality cationic cellulose product but will also help conserve resources that could be utilized for the production of other valued products elsewhere in the near future.

Quasi-solid supercapacitors are promising electrochemical devices for energy storage applications due to their high-power density, long life cycle, and environmental benefits. However, their electrochemical performance can change over time as a result of interactions between the electrodes and electrolyte, as well as the fabrication process. In this study, the electrochemical behavior of quasi-solid supercapacitors with activated carbon electrodes immersed in 4 M H₂SO₄ poly(vinyl alcohol) electrolyte for periods of 10 min and 24 h were investigated. Initial measurements show a lack of energy storing properties in newly fabricated devices, which improve with the aging time, as observed in cyclic voltammetry and charge–discharge cycles. Anticlockwise arcs and resonant peaks were observed in Nyquist and Bode plots, respectively, and were modeled by introducing complex conjugate roots and a damping factor ξ in the transfer function of the electronic equivalent circuit. This unfavorable behavior disappeared after 14 days in devices with shorter immersion times. On the other hand, the effects persisted in devices with longer immersion times even after 28 days. The stability of quasi-solid supercapacitors is thus demonstrated to be linked to complex conjugate roots and resonant behavior in impedance spectroscopy.

This work examined the simple synthesis of a multifunctional nanomaterial based on MoS₂ and g-C₃N₄ nanosheets (NSs) combination for the dual, adsorption-based and photocatalytic degradation-based removal of Rhodamine B (RhB), sildenafil citrate (SLD), and fluoxetine (FLX) from water. The study intended to identify the best ratio of MoS₂ to g-C₃N₄ to obtain the best adsorption and photocatalytic performances; therefore, the MoS₂@g-C₃N₄ nanocomposites were synthesized with four different ratios of MoS₂ NSs and g-C₃N₄ NSs, then characterized with FT-IR, XRD, and SEM techniques. Consequently, MoS₂ to g-C₃N₄ (3) was identified to be the most effective nanomaterial with outstanding adsorption and photocatalyst abilities. The specifically optimized nanocomposite was further experimented with for SLD and FLX removal, demonstrating high efficiency regarding all pollutants with the highest adsorption percentage at pH 4.0 for RhB, pH 8.0 for SLD, and pH 9.0 for FLX, respectively. A higher photocatalytic degradation rate was realized under UV light with complete decolorization of RhB in 300 min and SLD in 210 min. Thus, the outstanding adsorption and photocatalytic ability of the MoS₂@g-C₃N₄ (3) nanocomposite material point toward the fact that it may be used to treat a wide range of environmental pollutants.

Hydroxypropylated starch was successfully synthesized, aiming to address the limitations of native starch, such as poor mechanical properties and water sensitivity, which hinder its application in biodegradable polymers. The modification process, conducted at 115–135 °C with propylene oxide (PO) molar ratios of 0.4–0.8 [PO molecule per OH of starch], effectively disrupted the native starch structure. FTIR and ¹³C NMR confirmed methyl group incorporation, with lower temperatures and higher PO ratios yielding greater modification. SEM and XRD analyses demonstrated complete gelatinization; although some short-range order structures are present, long-range structures were eliminated, while DSC confirmed the absence of gelatinization peaks. TGA revealed the integration of lower molecular weight molecules, suggesting PPO homopolymerization within the starch granules. These structural transformations enhance the feasibility of producing hydroxypropylated starch films with reduced plasticizer content and energy requirements, offering a novel approach to improving starch-based materials for biodegradable applications.

Prunellate A (1), an unprecedented lignan lactone bearing a 6/7/6/5 tetracyclic system with C-2–C-2′ and C-7–C-8′ single bond linkage, probably derived from the rearrangement of methyl rosmarinate (2), has been isolated from the medicinal plant Prunella vulgaris. An extensive interpretation of multispectroscopic data including HRMS, IR, 1D, and 2D NMR elucidated its structure. The stereochemical assignment was conclusively established through electronic circular dichroism (ECD) experiments. The possible biosynthetic routes for the rearrangement from 2 to 1 were deduced. The antifibrosis activity was tested according to the traditional application of raw materials. Prunellate A exhibited a significant inhibition effect against TGFβ1-induced activation on LX-2 cells by targeting the Farnesoid X Receptor (FXR). These results indicated that prunellate A has great potential for use in the treatment of liver fibrosis.