ChemNanoMat最新文献

The valorization of spent battery components into high-performance functional materials presents a promising avenue for sustainable resource management. In this study, we successfully recovered and repurposed materials from spent alkaline batteries, separating them into carbon-based cathode powders (black fraction) and zinc (Zn)-based anode powders (white fraction). While the cathode material consists primarily of carbon and oxygen, the anode material comprises Zn-based compounds, including zinc oxide (ZnO). We demonstrate that simple calcination treatment at 80°C transforms the recovered Zn-based powder (DW_V-80) into a highly efficient photocatalyst. X-ray diffraction analysis reveals the optimized material as a crystalline composite of ZnO and zinc nitrate hydroxide hydrate (Zn₅(NO₃)₂(OH)₈·2H₂O), exhibiting superior photocatalytic H₂ evolution activity, producing ≈350 μmol of H₂ in 5 h. In contrast, the carbon-based materials showed negligible photocatalytic activity. The enhanced performance of DW_V-80 is attributed to the synergistic effect between the two crystalline phases and optimal concentrations of structural defects, such as oxygen vacancies, induced by mild thermal treatment. This work highlights a simple yet effective strategy to upcycle waste battery materials into valuable photocatalysts for solar fuel production.

The photocatalytic reduction of carbon dioxide into valuable products is seen as a leading approach to tackle environmental challenges and energy crises. Metal-organic framework (MOF) has emerged as highly attractive photocatalysts for carbon dioxide (CO₂) reduction reactions because of excellent visible light absorption, tunable optical properties, well-defined active sites, post-modification capabilities, and superior stability. This review summarizes recent advances in the synthesis methods and catalytic performance of transition metal MOF for CO₂ reduction. Moreover, it identifies challenges and outlook for transition metal MOF applications, thereby establishing a foundation for both fundamental research and practical applications.

The reduction of graphene oxide is a key breakthrough for the industrial application of graphene. Conventional chemical and thermal routes often involve hazardous reagents or high temperatures, while microwave- and laser-based techniques, despite offering rapid bulk heating and precise patterning, remain constrained by their underlying mechanisms. Low-temperature plasma technology, with its green, efficient, and precisely controllable characteristics, provides a promising pathway to address this challenge. This article systematically reviews graphene oxide reduction technologies, with a particular emphasis on plasma-based strategies, analyzing liquid-phase and gas-phase plasma mechanisms and comparing reducing and inert atmospheres in terms of reaction pathways, reduction efficiency, and structure–property relationships of reduced graphene oxide. A key insight is that, compared with flammable reducing gases (H₂, CH₄), plasma reduction in a pure inert atmosphere (e.g., Ar) offers superior safety and environmental benefits. High plasma activity, uniform discharge, and high-quality graphene can be achieved by optimizing electrode structures (three-electrode dielectric barrier discharge) and dual-power-source modes (nanosecond pulse/AC). Future work should integrate inert-atmosphere plasma with other advanced reduction strategies to address challenges related to process scalability, reproducibility, and device-level integration, accelerating industrialization in flexible electronics and energy storage devices.

Transition state theory effectively describes solute transport in membranes, where molecular-level mechanisms dictate the energy barriers involved. Based on this theory and insights from natural systems, our study centers on UiO-66-NH₂, a metal–organic framework (MOF) with specific binding sites for fluoride ions, resembling the structural features of biological fluoride ion channels. Using a secondary solvothermal growth method, we fabricate a dense and continuous polycrystalline UiO-66-NH₂ membrane on an anodic aluminum oxide substrate. This membrane features subangstrom pores (3.12 and 6.28 Å), which precisely sieve fluoride ions by facilitating selective dehydration and binding. Additionally, the high porosity and surface area of the membrane enhance ion flux while maintaining excellent selectivity. The strong Zr–F interactions within the channel play a pivotal role in reducing the activation energy required for F⁻ transport, resulting in efficient separation compared to other anions, with the F⁻/SO₄²⁻ selectivity reaching 169. This work sheds light on the fundamental ion transport mechanisms in subnanochannels and highlights the potential of MOF membranes for advanced ion separation applications.

The catalytic performance of metal oxides is profoundly influenced by their crystal phase, yet the underlying mechanism often remains elusive. Herein, we systematically investigate the crystal-phase-dependent activity of indium oxide (In₂O₃) for the electrocatalytic CO₂ reduction reaction (CO₂RR) to formate. Through a solvent-controlled hydrothermal synthesis, we prepared phase-pure cubic (c-In₂O₃) and hexagonal (h-In₂O₃) polymorphs. Electrochemical evaluations reveal that h-In₂O₃ significantly outperforms c-In₂O₃, achieving a superior formate Faradaic efficiency of 86.3% at −0.8 V versus reversible hydrogen electrode and demonstrating a notably higher partial current density across a wide potential window. In situ attenuated total reflection surface-enhanced infrared absorption spectroscopy identifies a more intense signal for the *OCHO intermediate on h-In₂O₃, indicating facilitated reaction kinetics. Density functional theory calculations reveal the origin of this enhancement: the predominant (104) facet of h-In₂O₃ not only strengthens CO₂ adsorption but also significantly lowers the energy barrier for the formation of the *OCHO intermediate, the rate-determining step. Furthermore, this facet concurrently suppresses the competing hydrogen evolution reaction and CO pathway. This work elucidates the intrinsic advantages of the hexagonal phase in In₂O₃-based CO₂RR electrocatalysts, providing a fundamental principle for catalyst design via crystal-phase engineering.

Sensing technology plays a crucial role in medical diagnostics, environmental monitoring, and public safety. However, conventional sensing methods remain limited in sensitivity, specificity, and stability under complex conditions. Programmable DNA nanostructures, exemplified by DNA origami, offer a transformative route to next-generation sensing platforms by leveraging their precise self-assembly capability and controllable stimuli-responsive mechanisms. In this review, we summarize the key advances in DNA nanostructure-based sensing from the perspective of response mechanisms and signal transduction, covering biosensing, chemical sensing, physical sensing, and multimodal sensing, with emphasis on design strategies, performance advantages, and potential applications across different sensing modalities. Finally, the current challenges impeding the practical application of DNA nanostructures in sensing are concluded, along with an outlook on future research directions.

Covalent organic frameworks (COFs), featuring rigid π-conjugated structures, high specific surface areas, open channels, and highly modular characteristics, have become one of the most intensively studied materials in various application fields. The construction strategy of donor–acceptor (D–A) type COFs involves the ordered connection of electron-donating donor units and electron-withdrawing acceptor units through specific covalent bonds, ultimately forming a highly ordered alternating D–A network. This article systematically summarizes the design strategies and structural modulation methods of such materials, and outlines their research progress in photocatalytic applications. Finally, the current challenges are analyzed and future prospects are discussed, aiming to provide theoretical guidance and practical insights for the rational design and application of high-performance D–A COF photocatalysts.

Room-temperature ammonia (NH₃) detection is crucial for environmental safety and human health. In this study, a ternary PANI@Au-TiO₂ ammonia-sensitive composite was synthesized via in situ polymerization of polyaniline (PANI) with simultaneous reduction of chloroauric acid to form Au nanoparticles, followed by ultrasonic compounding with TiO₂ nanoparticles. The structural and morphological characterization confirmed the uniform distribution of Au and TiO₂ nanoparticles in the PANI matrix. Gas sensing experiments demonstrated that the PANI@Au-TiO₂ sensor exhibited markedly enhanced NH₃ response, achieving a high sensitivity of 0.0527/ppm compared to PANI, PANI@Au, and PANI-TiO₂ counterparts. Moreover, the PANI@Au-TiO₂ ternary composite sensor displayed excellent linearity within the NH₃ concentration range of 3–30 ppm, along with a low detection limit, good repeatability, and high selectivity toward ammonia. The enhanced performance is attributed to the synergistic effects of the p–n heterojunction, Schottky junction, and catalytic activity of Au nanoparticles, which facilitate efficient charge transfer and amplify the interaction with NH₃ molecules. These findings demonstrate that the hybrid sensing film based on PANI@Au-TiO₂ ternary composites exhibits excellent ammonia detection performance at room temperature, thereby offering a promising pathway for the development of advanced ammonia sensors.

Lithium–oxygen batteries (LOBs) have been widely investigated as one of the next generations of potential energy storage devices due to their high theoretical energy density (3500 Wh kg⁻¹), low cost, and small size. However, the performance of LOBs in practical applications is still not ideal. One of the vital bottlenecks is that the discharge product lithium peroxide (Li₂O₂) is insoluble in organic electrolytes and self-insulation and cannot be completely decomposed during the charging process. In addition, the incompletely decomposed Li₂O₂ blocks the electrode channel and covers the active site of the catalyst, eventually leading to fatal problems such as an increase in overpotential and a decrease in the cycle life of the battery. To solve the difficulties in the decomposition of Li₂O₂ in LOBs, this work systematically reviewed the strategies for promoting Li₂O₂ decomposition by developing a new electrolyte to improve the solubility of Li₂O₂, designing a new system or an efficient catalyst to boost the kinetics of the oxygen reduction/oxygen evolution reaction (ORR/OER), and regulating the morphology of the formed Li₂O₂. This review provides guidance and ideas for the design of a new generation of high-performance LOBs.

This study aims to design interconnected oriented crystalline domains of silver nanoparticles using a template-free, solvent-evaporation-induced method with ample coverage over the substrate. The formation of these interconnected, oriented crystalline domains was confirmed by field emission scanning electron microscopy (FESEM) and grazing- incidence small-angle x-ray scattering (GISAXS), indicating the presence of crystalline domains with particles arranged in an ordered manner within each domain, while the domains are connected randomly. The lateral spacing between nanoparticles in the domains was calculated using GISAXS. The effect of nanoparticle concentration on the interconnectivity of the domains was demonstrated. The importance of the lateral distance between nanoparticles and the presence of domains close to each other, i.e., the interconnectivity of the domains, was showcased for the efficacy of these substrates for surface-enhanced Raman spectroscopy (SERS)-based detection. The efficacy of the interconnected oriented crystalline domains as a SERS substrate was demonstrated using Rhodamine 6G (R6G) dye and Monosodium glutamate (MSG) as the probe molecules.