Good Conductivity Research Articles

SnIn4S8/FeNi2P Z-scheme heterojunction hollow nanorods for photocatalytic hydrogen production

Climate change and natural disasters have stimulated the exploration of renewable energy, photocatalytic hydrogen production utilizing solar energy is considered an effective way. In this study, hollow FeNi2-MIL-88 nanorods were synthesized by the hydrothermal method, and then FeNi2P was obtained by gas phase phosphorization. Finally, SnIn4S8 was utilized to coat the surface of FeNi2P through an in-situ growth method to obtain rod-like SnIn4S8/FeNi2P. The results showed that the hydrogen production of SnIn4S8/FeNi2P reached 18083.93 μmol/g within 3 h. And SnIn4S8/FeNi2P showed good stability. The photocurrent response spectra and electrochemical impedance spectra confirmed that SnIn4S8/FeNi2P had good carrier conductivity and effectively inhibited the reorganization of photogenerated carriers. The modification of SnIn4S8 enabled the construction of a Z-scheme heterojunction between SnIn4S8 and FeNi2P. It provided more active sites and promoted the separation of photogenerated carriers, ultimately improving the hydrogen production performance of the SnIn4S8/FeNi2P photocatalyst. It would offer essential insights into the design and development of efficient MOFs-derived photocatalysts.

Experimental Verification of Inter Relation between Fowler–Nordheim and Millikan–Lauritsen Plot in Chemically Synthesized Zinc Oxide System

AbstractCold cathode emission or cold field emission (CFE) is a purely quantum mechanical phenomenon and a phenomenon of wonder. The exact science behind the observed current (I)–voltage (V) is yet to be pin pointed. For instance, a good cold emitter is very reasonably supposed to have low work function and good conductivity whereas a carbon allotropes like diamonds have just the reverse in both the cases, i.e., it is insulating in nature having very wide band gap as well as high work function yet it is considered to be an efficient field emitter. Since early of 20th century, till its middle a number of groups have suggested different equations or relations that can adequately describe the experimental CFE I–V characteristics adequately. Although they all fundamentally follow an exponential law, but so far, the relation suggests by Fowler and Nordheim (F–N) is the most accepted one. However, there is another relationship suggested by Millikan and Lauritsen (M–L) which is in spite of being reasonable not so common now a day to use. This work revisits different popular approaches for analyzing cold emission data. With this aim, the experimental CFE data obtained for chemically synthesized zinc oxide nanorods are chosen. The proper phase formation of ZnO is confirmed by XRD study whereas FESEM shows the rod like morphology. EDX confirms the proper stoichiometric ratio for the sample. After detail analysis it is confirmed that the theoretically proposed relation between F–N and M–L experimentally holds good as well and thus it would not be wrong to analyze the CFE data by simple M–L theory.

The Corrosion Characteristics of Graphite Coatings on Nickel Foam and Their Applications in High-Temperature Proton Exchange Membrane Fuel Cells

This study investigates the effectiveness of graphite coatings on nickel foam for use in high-temperature proton exchange membrane fuel cells (HT-PEMFCs). Nickel foam, known for its high porosity and good conductivity, serves as an advantageous alternative to traditional flow channels but faces corrosion challenges in HT-PEMFCs, especially from phosphoric acid leakage. Graphite coatings are used as the protection layer and compared with nitride coatings. Chemical vapor deposition process parameters are first optimized for graphite growth. Corrosion polarization curves are then measured using a high-temperature phosphoric acid three-electrode system simulating HT-PEMFC conditions, followed by an analysis of the surface morphology of the samples. Subsequently, the performance and durability of the nickel foams with different coatings are evaluated after being assembled in single fuel cells. The results highlight the superior corrosion resistance of graphite coating under HT-PEMFC conditions, demonstrating its performance over other coatings. Graphite-coated foams showed a significant reduction in corrosion current, approximately 58% lower than uncoated foams and 21% lower than the TiN coated foams. In practical applications, an HT-PEMFC single cell with graphite-coated nickel foam demonstrated a current density of 763 mA/cm2 at 0.6 V under conditions of 180 oC and 2 atm H2/air. The current density is 40% higher than that of the uncoated nickel foam. The results show notable long-term durability under constant current holding tests at 160 oC. The voltage decay rate in the graphite-coated cell was 48% lower compared to the cell with uncoated nickel forms.

Study Effect of rGO Addition on Photocatalytic Activity of TiO2 in Reducing Carbon Dioxide Using Electrochemical Method

Abstract Increasing the carbon dioxide (CO2) concentration every year can cause various environmental problems. One of the technologies to reduce CO2 is carbon capture. The semiconductor of TiO2 is widely used as a photocatalyst to reduce CO2. However, TiO2 has limitations in absorbing light in the visible region because it has a large band gap value. Besides, TiO2 has a fast recombination of electron-hole pairs so it can reduce photocatalytic activity. An addition of rGO is expected to cover the shortcomings of TiO2 because rGO has good conductivity and a small band gap. We synthesized rGO-TiO2 photocatalyst and measured its activity in capturing and converting CO2 using an electrochemical method. By using voltage difference as an electron driver in reacting with CO2 we observe the reaction between electrons and CO2. The measurements were carried out under irradiated and unirradiated conditions. The CV measurements show that the rGO-TiO2 electrode with 60% rGO content has reduction and oxidation peaks. Based on the electrochemical half-reaction table, the reduction peaks in unirradiated conditions indicate the conversion of CO2 to CH4 and (COOH)2, while under irradiated the reduction peak indicates the formation of HCOO− and CH2CH2. The results show that by using the rGO-TiO2 composite as an electrode not only reduces CO2 but also converts the CO2 into hydrocarbon.

Lanternarene-Based Self-Sorting Double-Network Hydrogels for Flexible Strain Sensors.

Conductive flexible hydrogels have attracted immense attentions recently due to their wide applications in wearable sensors. However, the poor mechanical properties of most conductive polymer limit their utilizations. Herein, a double network hydrogel is fabricated via a self-sorting process with cationic polyacrylamide as the first flexible network and the lantern[33]arene-based hydrogen organic framework nanofibers as the second rigid network. This hydrogel is endowed with good conductivity (0.25 S m-1) and mechanical properties, such as large Young's modulus (31.9MPa), fracture elongation (487%) and toughness (6.97MJ m-3). The stretchability of this hydrogel is greatly improved after the kirigami cutting, which makes it can be used as flexible strain sensor for monitoring human motions, such as bending of fingers, wrist and elbows. This study not only provides a valuable strategy for the construction of double network hydrogels by lanternarene, but also expands the application of the macrocycle hydrogels to flexible electronics.

Electrochemical biosensor based on copper sulfide/reduced graphene oxide/glucose oxidase construct for glucose detection

Due to the current increase in the number of people suffering from diabetes worldwide, how to monitor the blood glucose level in the human body has become an urgent problem to be solved nowadays. The electrochemical sensor method can be used for real-time glucose monitoring due to its advantages of real-time monitoring capability and high sensitivity. Reduced graphene oxide (rGO) has great potential for application in the field of sensors due to its advantages of large specific surface area, high stability, and good electrical and thermal conductivity. Meanwhile, the synergistic effect between two-dimensional transition metal sulfides and graphene can improve the electrochemical performance of materials due to their similar mechanical flexibility and strength. This article uses flake graphite, copper sulfate, and glucose oxidase (GOx) as raw materials to prepare CuS/rGO/GOx/GCE electrodes, and explores the performance of electrode electrocatalysis for glucose. The results showed that the prepared sensor was characterized by a low detection limit (1.75 nM) and a wide linear range (0.1-100 mM) for glucose detection, displaying a good overall detection performance, and its sensing mechanism and dynamic process were also investigated. In addition, the sensor has outstanding selectivity, anti-interference, repeatability, reproducibility and practicality.

Density functional theory study of cobalt sulfide as a counter electrode material for dye-sensitized solar cells

Abstract Dye-sensitized solar cells (DSSCs) are viewed as potential substitutes for traditional silicon-based solar cells due to their affordability, impressive performance in low-light conditions, eco-friendly energy production, and adaptability in solar product integration. The use of noble metals such as platinum as counter electrodes in DSSCs was initially limited by their high cost; however, cobalt sulfide has been recognized as a viable alternative due to its abundance, non-toxic properties, and cost-effectiveness. In this work, the crystal structure, electronic, optical characteristics and electrocatalytic activity of the tetragonal phases of cobalt sulfide are investigated through density functional theory with a quantum espresso package. The results obtained for the lattice parameter are a = b = 3.53 Å and c = 4.80 Å. The generalized gradient approximation and hybrid exchange correlation function yield bandgaps of 1.63 and 1.69 eV, respectively, which are consistent with the reported experimental values. An analysis of the density of states and the projected density was carried out to validate the accuracy of the calculated band gaps. Additionally, significant information was obtained from the optical properties through the calculation of the dielectric function. The findings reveal real and imaginary static dielectric constants of 11.85 and 0.13, respectively. Furthermore, the measured absorption and conductivity spectra exhibit promising attributes in the UV–visible range and good electrical conductivity. Moreover, the electrocatalytic activity was studied to analyze the adsorption energy of CoS and the electrolyte. Generally, the calculated electronic and optical properties of CoS crystals indicate their potential application as counter electrodes in dye-sensitized solar cells.

Comprehensive analysis of polyethylene glycol – lauric acid as a promising phase change material: Spectroscopic, thermal, and quantum insights

The increasing need for effective and environmentally sustainable energy storage technologies has delineated phase change materials (PCMs) as prospective candidates for thermal energy storage applications. In this study, we thoroughly analyzed polyethylene glycol (PEG 400) and lauric acid (LA) as promising PCMs by applying spectroscopic study, thermal, and quantum approaches. The thermal stability and chemical compatibility of PEG – LA were investigated using FTIR and Raman spectroscopy, revealing that optimal molecular interactions and structural changes occur at temperatures ranging from −10 °C to 30 °C, especially at higher LA volume fraction (VLA ≥ 60 %), as evidenced by marked blue shifts in the Raman spectra. TGA demonstrated the 2-step degradation of the PEG – LA (6:4), representing good material stability and high thermal conductivity enhancement of 32.24 % due to synergistic interactions among PEG and LA. DSC analysis established a high capacitive energy storage of 181.5 J/g and a phase transition of solid–liquid at room temperature (30–40 °C), which better crystallization properties based on higher LHR and supercooling degree compared with pristine LA. The thermal cycling reliability and FTIR spectra demonstrated the thermal and chemical stability of PEG – LA even after 1000 cycles. Quantum DFT analysis verified the experimental results, exhibiting robust hydrogen bonding interactions that contribute to the thermal stability, phase transition processes, higher energy storage capacity, and reactivity of PEG – LA. These results highlight PEG – LA as a promising and effective PCM for various thermal energy storage applications.

Balancing PEDOT:PSS conductivity for optimal power output of p-n junction based ZnO piezoelectric nanogenerator

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid) (PEDOT:PSS), has been employed in a wide range of applications owing to its good film-forming properties, high transparency, tunable conductivity, and good thermal and environmental stability. In piezoelectric nanogenerators (PENGs), p-type PEDOT:PSS has been used to form a p-n junction with n-type ZnO nanorods, which slows down the screening of the piezoelectric polarisation to increase the generated output voltage. Optimizing the conductive property of PEDOT:PSS is therefore a potential way to improve the performance of a PENG by controlling the screening effect and internal resistance of the device. In this work, ethylene glycol (EG) is added to the PEDOT:PSS layer in a ZnO PENG to modify its conductivity. Doping with EG, induces a change in conformation of the PEDOT which transform from a coil shape to expanded-coil or linear shapes as confirmed by Raman spectroscopy. The conductivity of the PEDOT:PSS layer is enhanced and the internal resistance of the PENG device is reduced, producing a higher current output. However, at the same time, devices using higher EG doping levels produce reduced voltage output, which is related to the rapid screening of the developed polarisation. Specifically, the optimal EG content was identified at 2.5%; although this resulted in a slight 4.0% reduction in voltage output compared to undoped devices, the current output increased by 41.6%, ultimately leading to a 33.1% improvement in peak power output. Therefore, we find that a balance between reducing the device resistance, which increases current output, and supressing the screening effect, which increases voltage output, is required to produce an optimum power output from the devices.

High-performance and ultra-robust triboelectric nanogenerator based on hBN nanosheets/PVDF composite membranes for wind energy harvesting

Triboelectric nanogenerator (TENG) is a novel energy technology that converts high-entropy mechanical energy from the environment into electrical energy using triboelectrification and electrostatic induction effects. However, the low surface charge density and easy wear of traditional triboelectric materials are bottlenecks for their practical applications. Here, a remarkable triboelectric properties, superior mechanical properties, exceptional wear resistance, and high thermal conductivity hexagonal boron nitride nanosheets (hBNNS)/ polyvinylidene difluoride (PVDF) composite negative triboelectric material is developed. The inclusion of hBNNS as an electron acceptor and nucleating agent not only effectively boosted the surface charge density (711 μC/m2) and mechanical characteristics of the composite membrane, but also the friction coefficient (COF) and thermal conductivity of the 2 wt% hBNNS/PVDF composite membrane decreased by 28.6 % and increased by 22.2 % compared to the PVDF matrix, respectively. The optimized TENG delivers a peak voltage of 434 V, a current of 53 μA, and a power of 4.84 mW. Furthermore, it exhibits exceptional ultra-robust, enabling continuous operation for 72 h at a wind speed of 17.5 m/s while maintaining performance above 90.6 %. Additionally, the TENG is capable of effectively powering a smart hygrothermograph and realizing wireless real-time monitoring, or directly lit up 102 white LEDs in a serial connection. This work addresses the challenges of low output performance and limited lifespan in TENG from a material perspective, providing a valuable reference method for the design of negative triboelectric materials with high surface charge density, good mechanical properties, low COF, and high thermal conductivity.

Al(Si)/Al2O3 and NiAl(Si)/Al2O3 co-continuous composites obtained by low temperature Reactive Metal Penetration of dense silica preforms.

Interpenetrating network Al(Si)/Al2O3 composites, obtained by a reactive metal penetration process, where pure aluminum metal reacts with a dense amorphous silica preform, are an interesting class of metal/ceramic composites, with two continuous networks of metal (Al-Si alloy) and ceramic (Al2O3). These composites have high stiffness and hardness, while retaining acceptable toughness and good thermal and electrical conductivity, and can be used in wear or thermal management applications. A second infiltration step with nickel allows to substitute the Al(Si) alloy with an intermetallic, obtaining an interpenetrating network NiAl(Si)/Al2O3 composite, with very high hardness and melting point. While in the standard process the temperature for obtaining the Al(Si)/Al2O3 composites is in the 1100-1200 °C range, in this paper we studied instead the 700-1000 °C temperature range and its effect on the microstructure of the final NiAl(Si)/Al2O3 composite. After the first infiltration step, the microstructure of Al(Si)/Al2O3 composites depends on both temperature and time of the treatment. At 700-800 °C and for reaction time of 1-2 hours, the grain size is completely sub-micrometric. When temperature and time of reaction increase, islands with a coarser microstructure, of micrometric size, form, reaching a fully micrometric coarser microstructure at 1100-1200 °C. The islands formation is due to the transformation from transition aluminas, formed at low temperature and low reaction time, to α-alumina, while at high temperature α-alumina forms directly. In a second step, the Al(Si) metal network was replaced with an intermetallic one, by contacting the composite with liquid nickel, that reacted with the Al(Si) alloy forming an Al-Ni-Si intermetallic. The temperature and duration of the first infiltration step strongly influences not only the microstructure of the Al(Si)/Al2O3 composite but also of the final NiAl(Si)/Al2O3 one, that is finer when the first step (reaction of aluminum with silica) occurs at lower temperature.

Fabrication of core–shell nickel ferrite@polypyrrole composite for broadband and efficient electromagnetic wave absorption

Herein, nickel ferrite@polypyrrole (NiFe2O4@PPy) composite was prepared by a simple two-step route of solvothermal synthesis and in-situ oxidation polymerization reaction. The results of micromorphology analysis showed that the obtained NiFe2O4@PPy composite had a unique core–shell structure, good magnetic performance and electrical conductivity. Furthermore, the as-prepared magnetic/conductive NiFe2O4@PPy composite exhibited notably enhanced electromagnetic wave (EMW) absorption performance than pure NiFe2O4 and PPy. When the filling ratio was 17.5 wt% and the matching thickness was 2.24 mm, the optimal minimum reflection loss (RLmin) of −56.25 dB and a broad effective absorption bandwidth (EAB) of 5.2 GHz were achieved for NiFe2O4@PPy composite. With slightly increasing the matching thickness to 2.6 mm, the maximum EAB of 7.12 GHz could be reached. Additionally, the probable EMW absorption mechanism was elucidated. Therefore, this work could provide a valuable reference for the preparation of magnetic ferrite/conductive polymer composites as broadband and high-efficiency EMW absorbers.

Structural and Electrochemical Characterisation of NBZFO Cobalt-Free Cathode Material for Intermediate-Temperature Solid Oxide Fuel Cells: An Experimental Investigation

Compared to other energy-generating technologies and energy conversion devices, intermediate-temperature solid oxide fuel cells (IT-SOFCs) have gained significant attention from energy experts due to its high energy density, moderate operating temperature (600–800°C), low emissions and reliability. Enhancing the performance of IT-SOFCs requires suitable and excellent cathode materials. Thus, a perovskite-type Nd0.5Ba0.5Zr0.8Fe0.2O3+δ (NBZFO) material was synthesised via traditional solid-state reaction technique and analysed as a potential cathode material for IT-SOFCs. Analysis of X-ray diffraction data (XRD) revealed a single-phase perovskite material that crystallises in cubic space group (pm-3m). The thermal and electrochemical properties were analysed with the aid of thermogravimetric analysis (TGA) and electrochemical impedance spectroscopy (EIS). NBZFO has an electrical conductivity in air of 80 S cm−1 at 400°C and a polarisation resistance (Rp) of 0.106 Ω cm2 at 800°C. TGA reveals a slight loss in weight of about 0.58%, thereby suggesting a highly stable cathode material for IT-SOFC. Electrochemical investigation shows that NBZFO has good electronic and ionic conductivity and excellent oxygen stichometry. Further studies are required to understand the effects of varying B-site composition of the cathode material.

Improving a shell-tube latent heat thermal energy storage unit for building hot water demand using metal foam inserts at a constant pumping power

The phase transition heat transfer during the melting and solidification processes of phase change materials (PCMs) was modeled in a shell-tube thermal energy storage unit. For the first time, special attention was dedicated to the heat transfer enhancement on the heat transfer fluid (HTF) side by placing metal foam (MF) inserts in the HTF tube. The MF inserts on the HTF side were placed next to the fin bases to produce the maximum heat transfer enhancement. A two-temperature local thermal non-equilibrium model was applied to accurately model the transient heat transfer in the MF domains. To perform a fair heat transfer analysis and consider the hydrodynamic aspects of heat transfer, the pumping power for driving the HTF fluid was kept fixed. The finite element method with automatic time-step control was used to integrate the model equations. Results show that the insertion of the MF in the HTF tube enhances conduction heat transfer but reduces flow for a constant pump power. Using a small amount of MF provides a good flow rate and a convective heat transfer while using a large amount of MF provides good conduction heat transfer but a poor flow rate and convection. A moderate amount of MF inserts results in poor conduction and a poor flow rate, notably increasing the phase transition time. A 5 % MF insert could provide about a 13 % shorter solidification time compared to a 25 % MF insert. Thus, a well-designed and engineered MF insert configuration on the HTF side can reduce the phase transition time and improve the energy storage power.

High-tear resistant gels crosslinked by DA@CNC for 3D printing flexible wearable devices

Photocurable gels have broad application prospects in biomedicine, bionics, flexible wearable devices and other fields. However, there are still some problems in the current photocurable gels, such as notch sensitivity, that is, poor tear resistance. In this study, we provided a photocurable gel with excellent tear resistance. The gel prepolymer is mainly composed of hydroxymethylacrylamide (NAM) and cellulose nanocrystals (CNC) modified with dopamine hydrochloride (DA), referred to as DA@CNC. After photocuring, the prepared gels show excellent mechanical properties such as tear resistance, elasticity and toughness. The introduction of DA@CNC not only endows gels with a large amount of energy dissipation through hydrogen bond crosslinking, but also effectively resists crack expansion as a nano-sized reinforcing phase, which greatly improves the tear resistance of the gels. Even at a 40 % gap, the elongation at break of the gel can still reach 1445 %. In addition, the DA can endow the gel with good electrical conductivity and excellent sensitivity (GF = 23.8). Some flexible wearable devices like finger sleeve and wristband can be customized by photocurable 3D printing using the gel with high toughness. This high-performance gel has great application potential in flexible wearable devices.

Rice husk-derived nitrogen-doped graphitic carbon/graphene nanosheets self-assembly for high-performance supercapacitors with chemical blowing method

Carbon materials derived from waste biomass are increasingly popular in energy devices due to their renewability, environmental benefits, and rich heteroatom functionalization. Herein, a simple and low-cost method for synthesising rice husk-derived nitrogen-doped graphitic carbon/graphene nanosheets (RNGNs) by chemical blowing was developed. Carbon was derived from rice husk (RH), while nitrogen was sourced from ethylenediaminetetraacetic acid and iron sodium salt hydrate (EDTA-FE), serving multiple roles as a blowing agent, an activating agent and a graphitization catalyst in a closed system. This approach facilitates the formation of a unique 3D structure of 2D graphene self-assembly on the wrinkled surface of graphitic carbon. As an electrode material for supercapacitors, the obtained RNGN800–1:1 with high nitrogen content (5.02 %) shows good electrical conductivity and a large specific surface area (1130 m2 g−1). These characteristics bring about an impressive electrochemical performance (334.5 F g−1 at 0.5 A g−1, 75.6 % retention at 20 A g−1). Moreover, when assembled into symmetrical device, the RNGN800–1:1 demonstrates a high power density of 9.4 kW kg−1and an excellent energy density of 15.2 Wh kg−1 with outstanding long-term cyclability (remains 94.77 % after 25000 cycles). This study introduces a straightforward and environmentally friendly approach for synthesizing nitrogen-doped graphitic carbon/graphene nanosheets from sustainable biomass resources. The resulting material is expected to have broad applications across various areas, including adsorption, catalysis, and energy storage.

Preparation and mechanism study of highly sensitive NH3 gas sensor based on Au-modified CdS nanoparticles

A high-performance ammonia (NH3) gas sensor based on Au nanoparticles (AuNPs) modified CdS (Au/CdS) was synthesized by hydrothermal method, and the sensing mechanism of Au/CdS was studied by first-principles based on density functional theory (DFT). Experimental results show that the addition of AuNPs can effectively enhance CdS-based NH3 gas sensor performance. Au/CdS sensor exhibits high response (16580), short response/recovery time (2.25 s/1.25 s), and low limit detection (500 ppb), good repeatability and stability. Because AuNPs can effectively increase the generation of sulfur vacancies on the surface of CdS, increasing the amount of chemisorbed oxygen and providing more active sites for NH3. Furthermore, the good conductivity of AuNPs promotes the separation and transport of carriers on CdS surface, thereby improving the gas sensing performance. DFT calculations indicate that the ionization energy of Au is less than that of Cd, which causes some Cd atoms to lose their coordination with S atoms and increase sulfur vacancies on the surface of CdS. In Au/CdS sensors, sulfur vacancies accelerate the cleavage of NH3, and resulting electrons participate in charge transport, thereby enhancing the adsorption energy. This study introduces a new method for fabricating high performance NH3 sensor based on CdS rich in sulfur vacancies.

A wide linear range and highly sensitive electrochemical reduction of environmental hazard (p-Nitrotoluene) using carbon-based hybrid composite (Ti3C2TX@MnCo2O4)

The electrochemical sensor is receiving much attention because of the evolving on-time sensing technology. It is crucial to develop new catalysts for electrochemical sensor applications with favorable physicochemical, electrocatalytic properties and good conductivity to meet the demands of on-time monitoring applications. The excellence of this research work is the preparation of Ti3C2TX@MCO nanocomposite by ultra-sonication method for the sensing of p-Nitrotoluene (p-NT). The prepared electrode material exhibits excellent electrocatalytic properties towards the sensing of p-NT compared with other electrodes. The p-NT was quantified by Differential Pulse Voltammetry (DPV) and Amperometric (i-t) techniques. The good linear range was observed by DPV (3–1860 μM) and i-t method (0.18 – 4170 μM). The calculated limit of detection (LOD) from DPV and i-t methods are 93.5 and 35.1 nM, respectively. The sensitivity values calculated from DPV, and i-t methods are 1.68 µA/µM. cm2 and 1.71 µA/µM. cm2, respectively. The proposed sensor system exhibits better selectivity, reproducibility, repeatability and stability for sensing of p-NT. A real time p-NT detection study was conducted using environmental water samples.

Co-MOF-derived N-doped carbon nanosheet arrays on biomass carbon fiber membrane for highly sensitive detection of luteolin

Rapid and accurate determination of luteolin (LU) content is important for drug dosage control, treatment and prevention of disease. Traditional chromatographic and spectroscopic methods are gradually replaced by more sensitive and rapid electrochemical detection. 3D carbonized eggshell fiber membrane (3D CEFM) with good electrical conductivity and mechanical stability is prepared at high temperatures. To enhance the sensing performance of LU, nitrogen-doped carbon nanosheet arrays/3D CEFM (Co-NC NSAs/3D CEFM) derived from ZIF-67 nanosheet arrays (ZIF-67 NSAs) are prepared on the surface of 3D CEFM. Due to the synergistic effect, the Co-NC NSAs (thickness ∼ 1 μm, height ∼ 3 μm) provides a shorter electron transport path, while the 3D CEFM (pore size ∼5 μm) offers good electrical conductivity and a large solution contact area. Co-NC NSAs/3D CEFM electrode has a sensitivity of 1.31 μA·μM−1·cm−2 in the 0–60 μM LU and a limit of detection (LOD) of 0.04 μM (S/N = 3). Meanwhile, the electrode demonstrated recoveries of 98.0 % to 103.5 % in real samples, with a relative standard deviation (RSD) of 1.2 to 2.3 %. These results indicate that the electrode has significant potential for practical applications.

Construction of Solution Processable NUS-8/PANI Nanosheets via Template-Directed Polymerization for Ultratrace Gas Sensing.

The advancement of wireless gas sensing signifies a substantial leap forward in gas detection and intelligent monitoring technologies. This necessitates stringent design criteria for gas sensitive materials with good solution processability, conductivity, and porosity, whose design and synthesis remain challenging yet highly sought-after. Herein, the fabrication of NUS-8/polyaniline (PANI) nanosheets is presented with excellent solution processability, high porosity, triboelectric property, and superior electrical conductivity via a template-directed polymerization strategy. Solution processable NUS-8 nanosheets, synthesized directly by a "one-pot" approach, serve as templates to enhance the "on-site" polymerization of aniline, resulting in the formation of PANI layer on NUS-8 nanosheets with a thickness of 7nm. The resultant NUS-8/PANI nanosheets exhibit outstanding solution processability, and a film conductivity of 8.6 Sm-1. The solution processability enables the facile fabrication of homogeneous and compact NUS-8/PANI films and thus their integration onto electronic devices targeted for multifunctional sensing. The NUS-8/PANI coated sensors demonstrate sensitive and selective detection at room temperature toward ultratrace ammonia with a detection limit of 120 ppb. A wireless sensing system based on the NUS-8/PANI-coated sensor is capable to monitor the spoilage process of meat. This study paves novel avenues for designing and synthesizing gas-sensitive materials for practical applications.