ChemNanoMat最新文献

Rice husk-derived biomass carbon holds strong potential in supercapacitor applications due to its sustainability and low cost. Herein, rice husk carbons are activated using KOH, NaOH, and their mixture, and their electrochemical properties are systematically evaluated. The NaOH-activated sample achieves the highest specific capacitance of 160.53 F g⁻¹ at 0.5 A g⁻¹, indicating superior charge storage ability. The mixed alkali-activated sample exhibits the best cycling stability, retaining 102.41% capacitance after 10000 cycles, along with the lowest internal resistance (0.05 Ω), reflecting excellent long-term performance and conductivity. The KOH-activated sample shows balanced behavior across (97.18% after 10000 cycles, 0.06 Ω, 154.12 F g⁻¹ at 0.5 A g⁻¹). These results suggest that the electrochemical performance is governed by the combined effects of multiple structural and chemical parameters rather than a single dominant factor. This comparative study highlights the distinctive advantages of each activation route and provides valuable insight for tailoring biomass carbon materials toward specific energy storage requirements. This study provides practical guidance for optimizing activation strategies to achieve high-performance, cost-effective supercapacitor electrodes from agricultural waste.

Water-soluble Bi₂O₃ and Bi₂S₃ quantum dots (QDs) are successfully synthesized using a novel, simple, and environmentally friendly one-pot method. X-ray diffraction and transmission electron microscopy analyses indicate that both Bi₂O₃ and Bi₂S₃ QDs are well-crystallized, with average diameter of 1.84 ± 0.02 and 2.96 ± 0.05 nm, respectively. The prepared QDs exhibit excellent fluorescence properties that remain stable over the long term. Notably, their fluorescence can be selectively quenched by Fe³⁺ with remarkable anti-interference capability. Furthermore, the fluorescence intensity demonstrates a strong linear correlation with the concentration of ferric ions across a wide range, facilitating effective detection of Fe³⁺. The mechanism underlying the fluorescence quenching by Fe³⁺ is primarily attributed to the overlap between the absorption spectrum of Fe³⁺ and either the excitation light or emission spectrum of Bi₂O₃ and Bi₂S₃ QDs. In addition, when compared to atomic absorption spectrophotometry and ultraviolet spectrophotometry for detecting Fe³⁺, the fluorescence method utilizing these prepared QDs offers enhanced operational efficiency and user-friendliness. This study not only broadens the application scope of bismuth oxide and bismuth sulfide in environmental monitoring but also provides significant insights for synthesizing water-soluble bismuth-based QDs.

Herein, the synthesis and catalytic performance of cobalt-based M–N–C materials are reported for the transfer hydrogenolysis of lignin-derived compounds. The Co-800 catalyst, comprising cobalt nanoparticles (CoNPs) and sub-nanometric Co(II) species embedded in a nitrogen-doped carbon matrix, demonstrates high activity and selectivity for CO bond cleavage in oxidized β-O-4 lignin model substrates using formic acid as a hydrogen donor. Subsequent acid treatment removes the CoNPs, yielding Co-800-AT, which retains significant catalytic activity, indicating that atomically dispersed cobalt species contribute to the observed reactivity. Both catalysts operate efficiently under mild conditions, with Co-800 maintaining high conversion and recyclability over multiple cycles. These findings underscore the promise of Co-based M–N–C systems as sustainable and robust catalysts for lignin depolymerization.

The current work shows how catalyst-free carbon nanospheres (CNS) can be produced utilizing straightforward one-step pyrolysis methods employing biowaste Caesalpinia sappan pods as a carbon precursor. The manufactured CNS with a particle size range of 40–50 nm that is obtained show a porous nature and contain more than 87% carbon. The synthesized CNS are used as potential antibacterial agents against E. coli and S. aureus by microscopic analysis. By observing the distorted cell envelopes of both E. coli and S. aureus compared with those of untreated cells, it is well understood that CNS, by binding to the outer envelope of cells, renders some changes in the peptidoglycan layer of both Gram-positive and Gram-negative microbes, which in turn restricts their further growth. This study confirms the first report of use of CNS as an effective antibacterial agent.

Catalytic oxidation can efficiently remove volatile organic compounds by converting them into carbon dioxide and water, while minimizing secondary pollution. Currently, with the rapid development of the new energy industry, ternary lithium-ion power batteries are facing a peak in decommissioning. These spent batteries contain valuable metal elements, such as Mn, Co, and Ni. Recycling them as raw materials for catalyst preparation not only reduces costs but also achieves a "waste-to-waste" strategy. Herein, delithiation etching of spent LIBs is performed using a high-concentration sodium carbonate solution under ultrasonic assistance, yielding NiCoMnOx powder. This powder is subsequently loaded onto attapulgite (ATP) via a mechanochemical method. During ball milling, nitric acid is introduced to leach a small amount of Mg²⁺ ions from the ATP. These Mg²⁺ ions are then doped into the NiCoMnOx lattice during the reaction, inducing lattice expansion. This lattice distortion generated increased oxygen vacancies and defects, thereby enhancing lattice oxygen mobility and improving oxygen activation capacity. The NiCoMnOx/ATP catalyst prepared with a LIBs-to-ATP mass ratio of 0.6:1 exhibits outstanding catalytic performance for toluene oxidation: achieving 99% conversion at 270 °C and demonstrating excellent stability during prolonged cycling tests.

The performance of an electrochemical energy system is largely determined by the electrode materials. Ideal electrodes should offer high energy density, high power density, and excellent cyclic stability. Cobalt hydroxide (Co(OH)₂), an electrode that blurs the boundary between batteries and supercapacitors, delivers high energy through battery-like faradaic reaction, exhibiting excellent rate capability and cyclic stability, as well as characteristics of supercapacitors. However, the correlation between its structure and electrochemical performance remains insufficiently summarized. This review systematically covers the preparation, structure, property, and electrochemical performance of Co(OH)₂. Particularly, emphasis lies on how the former three factors influence electrochemical response and performance, and how their modulation can be leveraged to enhance the latter. Concomitantly, it discusses recent advances in developing the relevant supercapacitor devices, gaining insights into energy storage mechanisms by using in situ electrochemical characterization techniques, and nanostructure engineering for optimizing the electrochemical performance of Co(OH)₂ electrode.

Carbon nanotube (CNT) films are expected to be applied to electrochemical electrodes owing to their physical and chemical robustness and large specific surface area derived from their network structure. However, because of their complex structural factors, such as chirality, dispersion, bundling, and film density, the optimal CNT structure that can be used for electrochemical electrodes has not been determined yet. Moreover, a virus-sensing technology that can be easily used outside of specialized locations is required. This study addresses these issues by first describing the effect of the micro- and nanomorphology of CNT electrochemical electrodes on virus sensing. Subsequently, a comparison of antigen–antibody reactions for CNT electrochemical electrodes fabricated using different synthesis methods, dispersants, and surface roughness is performed. Results indicate that CNTs with high conductivity and antibody modification have the optimal structure for use in electrochemical electrodes. Moreover, highly sensitive norovirus sensing with a limit of detection of 1 fg mL⁻¹ is accomplished. A relationship between the CNT structure and electrochemical reactions is unprecedentedly elucidated. Thus, this study can serve as a guideline for developing high-performance electrochemical electrodes.

While conventional anticancer nanomedicine primarily focuses on using polymeric or lipid nanoparticles to deliver therapeutic agents, an emerging alternative approach is to turn the enzymes overexpressed by tumor cells as the catalysts for in situ self-assembly within cancer cells or the tumor microenvironment. In recent years, advancements in this field have shifted the role of self-assembling motifs from carriers of known drug molecules to a new class of anticancer therapeutics themselves. The rapid progress of this emerging field necessitates a brief review to highlight its unique concepts and features, which revert a main drug resistance mechanism to a tumor targeting advantage. Herein, recent representative examples of in situ nanomedicine generated by enzyme-instructed self-assembly are discussed, categorizing them based on the specific enzymes that trigger the self-assembly process. The critical role of molecular design in optimizing therapeutic efficacy and selectivity is emphasized. In the perspective and outlook, insights into the advantages of this approach are offered, while also addressing the key challenges that must be overcome to translate these strategies toward clinical applications. This review underscores the potential of enzymatic in situ nanomedicine as a complementary strategy to molecular therapy in cancer treatment.

In this study, molecular dynamics (MD) simulations are used to investigate the adsorption of a 21-nucleotide microRNA (miRNA21) to silica surfaces at three pHs, three salt concentrations, and with two salt species. Silica gel has been reported to be an effective biopreservation medium. MD simulations provided molecular-level details of the adsorption processes that are expected to affect preservation efficacy. Parallel tempering metadynamics in the well-tempered ensemble enhanced MD sampling and allowed the exploration of adsorbed, desorbed, compact, and extended miRNA21 conformations. Both CHARMM and AMBER force fields are used to explore conformational states. Simulation results indicate that higher salt concentrations correlate to increased binding strength, emphasizing the pivotal role of ion coordination in the adsorption process. Salt-mediated miRNA–silica interactions are observed, indicating that cations can allow miRNA to approach the silica surface even when the surface is negatively charged. Simulations also revealed that acidic environments significantly weaken the adsorption between miRNA21 and silica surfaces due to fewer salt-mediated interactions. These findings highlight the influence of environmental factors and salt-mediated bridging interactions on RNA-silica adsorption affinity. Simulations suggest that kinetics drive experimentally observed preservation activity. Reweighting of biased trajectories reveal key differences in RNA folding and ion coordination between force fields.

Under energy and environmental challenges, photocatalytic CO₂ reduction (PCR) has received much attention as a sustainable and clean energy conversion technology. BiVO₄ is noted for its excellent photochemical stability and suitable bandgap width. However, single BiVO₄ is still plagued by rapid carrier recombination and low reduction during PCR. Constructing an S-scheme heterojunction represents an effective strategy to address these challenges. This article summarizes the up-to-date advancements in BiVO₄-based S-scheme heterojunctions for PCR. The design strategies, synthesis methods, and characterization means of these heterojunctions are explored. The applications of S-scheme heterojunction constructed by coupling BiVO₄ with metal−organic frameworks, carbon-based materials, perovskites, and metal oxides/sulfides in PCR are highlighted. This review proposes novel design strategies of S-scheme heterojunctions for efficient PCR.