FlatChem最新文献

The limited specific capacity of graphite anodes constrains the advancement of lithium-ion batteries (LIBs), sodium-ion batteries (NIBs), and potassium-ion batteries (KIBs). To address this, we have explored the potential of van der Waals heterostructures for high-performance anode materials. Specifically, we designed and analyzed the NbS₂/Ti₂CS₂ heterostructure through first-principles calculations. This heterostructure demonstrates superior thermal stability and metallic conductivity. Furthermore, it allows for the stable adsorption of Li/Na/K atoms, indicating strong interactions that are advantageous for battery applications. Notably, the Li/Na/K ion diffusion barriers on NbS₂/Ti₂CS₂ are lower compared to other anodes, enhancing ion mobility. The average open-circuit voltages (OCVs) for NbS₂/Ti₂CS₂ as an anode in NIBs/KIBs range from 0 to 1 V, with a remarkable specific capacity of 489 mAh/g for NIBs. These findings position NbS₂/Ti₂CS₂ as an exceptional candidate for next-generation battery anodes, potentially revolutionizing the LIB/NIB/KIB landscape. Our research contributes to the ongoing development of advanced anode materials, offering new pathways for enhancing battery performance.

Importance of process parameters on thermal, microstructural, and magnetic properties of synthesized core/shell nanoparticles was investigated during their production via chemical vapor deposition (CVD). Herein, iron(II) sulfate heptahydrate and fumed silica powders were mixed in ethanol, and the solution was used for precursor preparation by utilizing spray dryer. These prepared precursors were treated in the CVD process under methane/hydrogen (CH₄/H₂) gas flow to synthesize graphene-encapsulated core/shell nanoparticles. CVD studies were performed at various temperatures (900–1000 °C), holding times (60, 90 min), and gas flow rates (100, 200 mL/min). After CVD studies, purification was applied to remove uncoated nanoparticles, and remaining fumed silica phases originated from the precursor via selective acid leaching using hydrofloric acid (HF) and hydrochloric acid (HCl) solutions. X-ray diffractometry, Raman and Mössbauer spectroscopy, Zeta potential measurement, thermogravimetry combined with differential scanning calorimetry, scanning and transmission electron microscopy/energy-dispersive spectroscopy, and vibrating sample magnetometry (VSM) results yielded the optimized CVD parameters as 950 °C, 60 min, CH₄/H₂: 1/1 and 50 mbar. The characterization results proved that multilayer graphene (d-spacing: 0.34 nm) encapsulated Fe/Fe₃C nanoparticles (average core size: ∼46.9 nm, shell thickness: ∼16.6 nm) can be successfully synthesized by using CVD process followed by a leaching treatment. VSM results revealed that synthesized nanoparticles had soft ferromagnetic properties (M_s: 90.6–185 emu/g; H_c: 255.4–301.6 Oe). Characterization results deepen the understanding of process parameters of CVD system on characteristics of core/shell nanoparticles.

Graphene nanosheets show great potential as electrode materials for supercapacitors due to their high surface area and excellent electrical conductivity. However, the low hydrophilicity of graphene nanosheets limits their electrochemical performance in aqueous supercapacitor applications. To enhance their electrochemical performance, we investigate the use of iodoacetic acid as an electrolytic functionalization agent for graphene nanosheets. Here, we demonstrate the successful electrolytic functionalization of graphene nanosheets under cathodic conditions in aqueous medium. The resulting material exhibits a high structural quality and carboxyl groups on the surface, which increases the hydrophilicity and wettability of the material. The applied voltage and the concentration of iodoacetic acid have been found to be key factors to optimize the process in order to get the maximum functionalization degree. The electrochemical performance demonstrates that iodoacetic acid functionalized graphene nanosheets exhibit significantly improved specific capacitance (220F/g at 0.5 A/g) and cycling stability of the symmetric cell compared to pristine graphene nanosheets, highlighting the potential of electrochemical functionalization to improve the performance of graphene-based materials in energy storage applications.

Zinc indium sulfide (ZnIn₂S₄) is a Cd-free semiconductor with great potential in various photocatalytic applications. However, its rapid photogenerated charge combination poses some challenges. Constructing ZnIn₂S₄-based heterojunction photocatalysts to address this has proven an effective solution. In this study, we loaded uniform Ni₃C nanoparticles as cocatalysts on layered ZnIn₂S₄ nanostructures to promote photocatalytic H₂ production activity. The optimal 3 % Ni₃C/ZnIn₂S₄ exhibited the highest H₂ generation rate of 393 μmol·g⁻¹·h⁻¹, 4.5 times greater than pure ZnIn₂S₄. The enhanced photocatalytic performance was ascribed to the incorporation of metallic Ni₃C, which provides more catalytically active sites and establishes electron transfer channels at the interfaces, facilitating the photogenerated carrier separation and H₂ production. The photocatalytic mechanism of Ni₃C/ZnIn₂S₄ was proposed through experimental measurements and DFT calculations. This study offers a way to develop efficient ZnIn₂S₄-based visible-light-driven photocatalysts.

Although chemotherapy remains a prevalent option in cancer treatment, its adverse effects on normal cells and suboptimal pharmacokinetics often limits its effectiveness. To address these challenges, this study successfully developed a new multifunctional drug delivery system comprising a covalent composite of graphene quantum dots and barium titanate nanoparticles. Notably, despite numerous reports on the surface modification of graphene quantum dots, studies focusing on cancer cell inhibition via different covalent bonds are scarce. To bridge this gap, this system was synthesized using eco-friendly esterification and amidation pathways. The anticancer drug doxorubicin was employed as a model drug, and hyaluronic acid was used to encapsulate the delivery system, enhancing its sustained release capabilities. Comprehensive material characterization confirmed the successful synthesis of the system. Its high drug loading capacity and acid-sensitive release can be attributed to the unique structure of the graphene quantum dots. Subsequent in vitro and in vivo biological evaluations not only demonstrated the system’s remarkable cancer inhibition efficacy but also accentuated the distinct impacts of the two bonding types. The underlying mechanism is believed to involve bonding affinity and electron transfer, findings that are corroborated by the experimental data. Additionally, results from animal models provide clear evidence for the potential application of this system (HA-DOX-GQD@BTNPs) in cancer therapeutics and imaging. In conclusion, this research elucidates the variances in drug carrier efficacy based on different covalent bond modifications for cancer treatment and introduces a novel drug delivery system that synergistically combines imaging and targeting capabilities.

Pseudocapacitors are well-known for performing redox reactions at the interfaces of electrode and electrolyte for storing and releasing energy competently. TiO₂ is thought to be a potential anode material for Na-ions batteries as it possesses the ability to store large sodium content at the interplanar spacing to amplify the electrochemical performances. However, for pseudocapacitors as anodes, the exact chemical mechanisms and the interaction among surface behavior and electrochemical properties are still needed to be explored. Herein this research, for the first time, monoclinic Na₄Ti₅O₁₂ nanowall arrays electrode (M−NTO NWAs) has been synthesized to investigate its structure, morphology and electrochemical characterizations as anode for supercapacitors (SCs). The mechanism of sodiation treatment for M−NTO NWAs as anode has elevated its excellent electrochemical properties. M−NTO NWAs is operated at a highly negative potential window between −1.0 and 0.0 V to achieve an excellent specific capacitance of 429 F/g, which is much superior compared to the HTO NSA electrode (295 F/g) and outstanding capacitance retention of ∼97 % is achieved after 3000 successive cycles at a high current density of 1 A/g. Enhanced electrochemical properties display the complementary contributions of structural involvement via the sodiation mechanism of M−NTO NWAs. Also, this work propels a new direction in utilizing ions insertion strategies to enhance electrode’s high performance for energy storage devices.

The method of monitoring food temperature during food storage needs to be improved to continuously and accurately perceive the temperature of the food in the package to ensure the quality and safety of the food during storage. This paper proposes and develops a battery-free flexible wireless temperature sensing system (BFTS) for food storage. The BFTS consists of a battery-free flexible wireless temperature sensing tag (BFTT), a wireless reader, and a personal computer (PC). The BFTT developed in this paper has good flexibility and can be placed inside the food package to realize the continuous monitoring of temperature changes. The flexible circuits of the BFTT were fabricated by laser engraving laser-induced graphene (LIG) −copper (Cu) plating film made with Cu plating on LIG. The LIG-Cu plating film has good thickness uniformity, electrical conductivity, and laser engraving processability. The antenna of BFTT has good performance. The wireless reader is connected to the PC using a data line, and the BFTT communicates wirelessly with the wireless reader using ultra-high frequency (UHF) radio frequency identification (RFID). The BFTT was realized by the wireless radio frequency (RF) as the supply power from the wireless reader. The BFTS could realize the temperature monitoring of food stored at 0℃ and −18℃, and it has the advantages of low cost, simple manufacturing process, and low energy consumption, which could be used to continuously and accurately monitor the inside temperature of the food packages. Overall, the LIG-Cu plating film developed in this paper could be used in the fabrication of flexible circuits, and the temperature monitoring inside food packages realized by the BFTS has potential applications in actual food storage.

Confined mass transport based on two-dimensional (2D) materials breaks the trade-off effect between permeability and selectivity, significantly enhancing the efficiency of mass transport. However, the prevailing view that mass transport performance is primarily determined by the structural design of molecules or ions within channels and the regulation of channel walls has led to the neglect of surrounding hydration layers. Recent studies indicate that the interactions between confined water and transport substances, particularly the formation of hydration shells, significantly influence the mass transport process. Therefore, a thorough investigation of the behavior and properties of confined water, especially its presence, regulation methods, and the enhanced mechanisms of mass transport in 2D channels is particularly urgent and constitutes an indispensable research direction for the future development of materials science and engineering technologies. This review summarizes the latest progress on 2D confined water including its structure, properties, and behavior under natural conditions or environmental influences, the mechanisms enhancing mass transport, and regulatory approaches, as well as multiple applications such as membrane separation, drug delivery, and confined reactions. Lastly, we present instructive perspectives on the current challenges and future directions in the study of confined water.

Biphenylene (BP) is a new member of the two-dimensional C nanomaterial family, and successful fabrication of BP offers an excellent opportunity for developing innovative C-based electronics. However, its unusual metallicity critically restricts its applications in field-effect transistors (FETs) and photocatalysis. Simultaneously, its relatively low work function (ϕ, 4.33 eV) seriously restricts its applications in anode materials of electronic devices. Therefore, understanding the tunabilities of electronic properties and ϕ of BP-based nanomaterials is crucial to guide experimental exploration; nevertheless, to date, little attention has been paid to this area. Herein, we theoretically demonstrate that conductivity of fluorinated BP (F_n-BP) evolves in the order metallic → semimetallic → semiconductivity with increasing F concentration, attributed to a bonding transition of BP (sp² → sp² + sp³ → sp³). Particularly, ϕ of BP can be significantly improved (4.82–6.97 eV) by fluorination, approximately two-fold higher than that of F_n-graphene owing to p electron transfer between F and BP. Consequently, metallic F_2D-BP and semimetallic F_4S-BP with favorable ϕs can be utilized as substitutes for Au and Pt anodes, respectively. Specifically, F_8D-BP, F_16D-BP, and F_24D-BP with exceptional band gaps of 0.40, 2.80, and 3.44 eV, respectively, exhibit high potentials for making channel materials in FETs, candidate materials in photocatalysis, and buffer layers in solar cells, respectively.

Two-dimensional hybrid organic–inorganic perovskite (2D-HOIP) crystals, in particular lead-bromide perovskites, exhibit great promise as scintillators due to their superior environmental stability compared to their 3D counterparts, offering high light yields and rapid decay times. These cost-effective, solution-processable materials demonstrate potential for efficient wide-energy radiation detection. In this paper we focus on investigating the effect of partial substitution of n-butylammonium (BA) cation with tert-butylammonium (t-Bu) cation within the butylammonium lead bromide (${\mathrm{BA}}_{2-x}{\mathrm{tBu}}_x{\mathrm{PbBr}}_4$) structure and its impact on luminescence and scintillation properties. We observe that inclusion up to 5 % of t-Bu (x = 0.1) within the structure leads to a narrowing of the bandgap, leading also to an improvement of the light yield by 10 % and lowering of the energy resolution, compared to pristine ${\mathrm{BA}}_2{\mathrm{PbBr}}_4$. The bandgap widens, compared to pristine ${\mathrm{BA}}_2{\mathrm{PbBr}}_4$, with higher concentrations above 5 %, resulting in effects for the scintillating properties of the 2D-HOIP at room temperature at t-Bu concentrations above 5 %, with reduced light yield and broadened energy resolution. Higher t-Bu concentration (x = 0.4) show very poor room temperature scintillation but increased efficiency at cryogenic temperatures below 50 K. The results shown in this paper demonstrate the fundamental limitation of organic cation mixing levels for scintillation efficiency enhancement.