Surface Electrical Conductivity Research Articles

Electrospun zein fibers loaded with pomegranate flower extract: Characterization and release behavior

In the present study electro-spinning technique was used to encapsulate pomegranate flower extract (PFE) in zein fibers. The effect of PFE concentrations (0%, 5%, 10%, and 15% (v/v)) on the electrospun solution properties, such as surface tension, apparent viscosity, and electrical conductivity were investigated. These effects on various fibers properties including morphology, thermal properties, structural characteristics, morphology, antioxidant and antimicrobial activity, encapsulation efficiency (EE), and release behavior was also evaluated. The results revealed that, increasing the PFE concentration (0–15%) led to increased surface tension and electrical conductivity and decreased the apparent viscosity of the electrospinning solution. This caused an increase in the fiber diameter from 217.1 to 722.2 nm with considerable EE (92.21–96.1%) and loading capacity (LC) (12.3–36.1%). Increasing the PFE concentration increased the surface hydrophilicity (contact angle of 93.21° and 57.82° respectively for 0 and 15% PFE loaded electrospun). Field emission scanning electron microscope (FESEM) results showed that all the fibers were uniform and free of beads. Also, molecular interaction between the PFE and zein has been confirmed with Fourier transform infrared (FTIR). DSC results indicated that the thermal stability were increased with increasing PEF concentration. The study also showed that the release of the PFE was slowest in a fatty food simulant. The primary release mechanism in simulated environments was Fickian diffusion. This research demonstrated that PFE loaded zein fibers can be used successfully in drug delivery, active packaging, and cosmetic products.

Corrosion and conductivity damage of AgNW transparent conductive thin films under a simulated sulfur-containing atmosphere and mechanical force

Silver nanowire (AgNW) transparent conductive thin films possess high flexibility, high conductivity, high light transmittance and etc., demonstrating significant advantages in flexible electronics applications. However, in the service occasions, the coupled effect of corrosion and mechanical force easily makes the electrical conductivity of AgNW films deteriorate or even fail, which seriously affects the service reliability of AgNW films. In this work, scanning vibrating electrode technique was firstly used to confirm the existence of electrochemical corrosion on AgNW films. Furthermore, electrochemical measurements (including OCP, PDP and EIS) were carried out for researching the electrochemical corrosion process on AgNW films under different environmental factors and mechanical forces. Their surface morphologies and electrical conductivity were characterized and evaluated by the Scanning Electron Microscopy and square resistance tester respectively. Experimental results indicate that the corrosion-mechanics interaction effect aggravates the damage process of electrical conductivity of AgNW films.

A novel electrochemical sensor based on aspartic acid polymer and carbonized-ZIF-67 for rapid sensing of arbutin

A novel electrochemical sensor modified by aspartic acid polymer and carbonized-ZIF-67 was prepared for arbutin detection. ZIF-67 was synthesized and carbonized, and then used as the substrate supporting of electrochemical sensor. Carbonized-ZIF-67 had a large specific surface and good electrical conductivity, which provided large electroactive area and promoted the electron transfer at the sensing interface. Aspartic acid polymer was prepared by cyclic voltammetry. Aspartic acid polymer could effectively absorb arbutin, resulting in the preconcentration of arbutin on sensor surface. Benefiting from the synergistic effect between carbonized-ZIF-67 and aspartic acid polymer, the prepared electrochemical sensor exhibited sensitive electrochemical response for arbutin. Under the optimum conditions, the electrochemical sensor achieved a wide linear range in the range from 5 to 110 μmol/L and a low detection limit of 0.41 μmol/L for arbutin. In practical application, the electrochemical sensor was employed to detect arbutin in green tea and whitening cream samples, exhibiting satisfactory recovery rates. With the outstanding features of easy operation, rapid response and high sensitivity, the prepared electrochemical sensor provided a convenient and effective tool for arbutin detection.

Surface-modified composites of metal–organic framework and wood-derived carbon for high-performance supercapacitors

The renewable nature, high carbon content, and unique hierarchical structure of wood-derived carbon make it an optimal self-supporting electrode for energy storage. However, the limitations in specific surface area and electrical conductivity defects pose challenges to achieving satisfactory charge storage in wood-derived carbon electrodes. Therefore, exploring diverse and effective surface strategies is crucial for enhancing the electrochemical energy storage performance. Herein, a decoration technique for enhancing aesthetic appeal involves applying a metal–organic framework (Ni/Co-MOF) containing nickel and cobalt onto the inner walls of wood tracheids. The sequential modification steps include carbonization, oxidation activation, and acid-etching. The Ni/NiO/CoO-CW-4 electrode, made by acid-etching carbonized wood (CW) doped with nickel, nickel oxide, and cobalt oxide for 4 h, has excellent surface area and pore size distribution, high graphitization degree, and exceptional conductivity. Furthermore, surface modification optimizes the surface chemistry and phase composition, resulting in a 0.8 mm thick Ni/NiO/CoO-CW-4 electrode with an exceptionally high areal capacitance of 16.76 F cm−2 at 5 mA cm−2. Meanwhile, the fabricated solid-state supercapacitor achieves an impressive energy density of 0.67 mWh cm−2 (8.38 mWh cm−3) at 2.5 mW cm−2 (31.25 mW cm−3), surpassing representative modified wood-based carbon electrodes by approximately 2–7 times. Additionally, the supercapacitor demonstrates exceptional stability, maintaining 96.21 % of capacitance even over 10,000 cycles. The parameters presented here demonstrate a significant improvement compared to those typically observed in most modified wood-derived carbon-based supercapacitors, effectively addressing common issues of low energy density and suboptimal cycling performance with wood carbon composites.

Detection of harmful gases (NO, NO2) by GaN@MoSSe heterostructures embedded with transition metal (Cu, Fe and Mn) atoms: A DFT study

Monitoring and identifying air pollutants, such as NO and NO2, is crucial due to their detrimental impact on both the environment and human health. This work employs density functional theory (DFT) with the PBE + U functional to investigate the adsorption and sensing performance of NO and NO2 on transition metal (TM)-doped GaN@MoSSe heterostructures. The adsorption energy, charge transfer, electron localization functions, charge density difference, spin density, band gaps and density of states are analyzed. The findings reveal that a transition from physisorption to chemisorption occurs after TM atoms doping. Also, when the surface is embedded with Cu, Fe and Mn atoms, there is a significant improvement in the behavior related to gas adsorption. The bandgap and its variations lead to the change in surface electrical conductivity, thereby affecting the gas sensitivity of the adsorption system. Particularly, the CuGa-GaN@MoSSe and FeGa-GaN@MoSSe systems exhibit improved gas sensitivity toward NO due to their significant band gap reduction. Meanwhile, the CuSe−MoSSe@GaN, CuGa-GaN@MoSSe, FeGa-GaN@MoSSe and MnGa-GaN@MoSSe systems also demonstrate enhanced sensing capabilities for NO2. This work offers valuable theoretical insights for exploring the potential applications of TM-GaN@MoSSe heterostructures in gas sensing.

Morphological and Doping Effects on Electrical Conductivity of Aluminum Metal Substrate through Pulsed Electrodeposition Coating of Cu-MWCNT

The demand for more efficient and sustainable electrical systems has driven research in the quest for innovative materials that enhance the properties of electrical conductors. This study investigated the influence of copper (Cu) coating and multi-walled carbon nanotubes (MWCNTs) on aluminum metal substrate through the pulsed electrodeposition technique. Parameters such as the concentration of chemical elements, current, voltage, temperature, time, and electrode spacing were optimized in search of improving the nanocomposite coating. The metallic substrate underwent anodization as surface preparation for coating. Characterization techniques employed included Field Emission Gun—Scanning Electron Microscopy (FEG-SEM) for analyzing coating morphology, Energy-Dispersive X-Ray Spectroscopy (EDS), Raman spectroscopy, and Kelvin probe for obtaining surface electrical conductivity values. Homogeneous dispersion of the Cu-MWCNTs film coating was achieved across the entire surface of the aluminum plate, creating a complex morphology. The doping effect was highlighted by changes in the vibrational characteristics of the nanocomposite, which affected the Raman spectrum dispersion bands. An increase in surface electrical conductivity by ≈52.33% compared to the control sample was obtained. Therefore, these results indicate that the improvement in the material’s electrical properties is intrinsically related to the complex morphology achieved with the adopted Cu-MWCNT nanocomposite coating process.

Synergistic Effect in MoS2 Nanosheets–Biochar Nanocomposites with Enhanced Surface Area and Electrical Conductivity for Energy Storage Applications

Synergistic Effect in MoS2 Nanosheets–Biochar Nanocomposites with Enhanced Surface Area and Electrical Conductivity for Energy Storage Applications

Assessment of Soil Physico-chemical Properties in Sugarcane Cultivation Areas of Navsari District, Gujarat, India

Sentinel 2 satellite data from the year 2021 were acquired from the Copernicus site to identify the sugarcane producing area in the Navsari district. Hybrid classification approach i.e., supervised and unsupervised with ground truth data were applied using ERDAS IMAGINE software. After image classification, 2.5 km x 2.5 km grid was prepared in Q-GIS software which along with classified sugarcane area were overlapped for site identification. Then, random soil surface and sub-surface samples were collected with reference from grid of intensive sugarcane growing area. The particle density (2.10 to 2.76 g cm-3 with the mean value of 2.58 g cm-3) and bulk density (1.10 to 1.68 g cm-3 with the mean value of 1.33 g cm-3) of surface soil were found to be lower than sub-surface soil (2.18 to 2.79 g cm-3 and 1.15 to 1.68 g cm-3 with the mean value of 2.62 g cm-3 and 1.42 g cm-3 respectively) while porosity (31.60 to 59.26% with the mean value of 48.39%) and maximum water holding capacity (22.77 to 51.92% with the mean value of 39.60%) of surface soil were found to be higher than sub-surface soil (29.54 to 57.71% and 20.98 to 48.91% with the mean value of 45.60% and 36.81% respectively). The pH of soil surface showed range from 6.08 to 8.37 while pH of soil sub-surface noted range of 6.00 to 8.50. The electrical conductivity of surface and sub-surface soil showed the range of 0.011 to 1.580 dS m-1 and 0.010 to 1.586 dS m-1. The soil organic carbon of surface soil ranged from 0.06 to 0.89% while that of sub-surface soil varied from 0.02 to 0.85%.

A disposable electrochemical sensor for amyloid-β42 protein based on molecular imprinted polymers with nitrogen doped carbon dots-graphene nanohybrid

This work presented a molecularly imprinted polymer (MIP) electrochemical sensor for determination of amyloid-β42 (Aβ42) as an Alzheimer’s disease (AD) biomarker. A nitrogen-doped carbon-dot-graphene (NCD-G) nanohybrid was synthesized through a simple ultrasonic method. Polypyrrole (PPY) was used as an imprinted polymer with an Aβ42 template for the electropolymerization process. The NCD-G and MIP were modified on a screen-printed carbon electrode (SPCE) without binding agent. The morphology and electrochemical properties of MIP/NCD-G modified SPCE were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–Vis spectroscopy, X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV) and square wave voltammetry (SWV). The developed sensor exhibited good linear response in a range from 5 to 70 pg/mL with a limit of detection (LOD) of 1 pg/mL under optimal conditions. This sensor shows excellent performance due to the enhancement of effective surface area, electrical conductivity, and electrocatalytic activity. This MIP sensor takes advantage of molecularly imprinted technique combined with nanohybrid to achieve high selectivity and sensitivity. Moreover, it possessed good reproducibility and miniaturization that could be applied as a platform for portable devices in healthcare in the future. Novelty statementThis work provides the combination of a zero-dimensional and two-dimensional materials, nitrogen doped carbon dots-graphene nanohybrid (NCD-G) by self-assembly through a simple ultrasonication method and applied as a molecularly imprinted polymer (MIP) sensor for determination of amyloid-β42 protein. We propose a minimum number of preparation steps which NCD-G could enhance the MIP sensor performance, owing to the synergistic effects with high selectivity and sensitivity. The hybrid formation of the carbon dots with graphene using their π-π interactions in carbon nanostructures. NCD-G nanohybrid and MIP modified on screen printed carbon electrode (SPCE) for the determination of amyloid-β42 have not been previously investigated. Moreover, this disposable strip is a single-use tool that might be essential for on-site devices.

Structural effect on physicochemical properties of ethanolamine carboxylate ionic liquids by experimental and theoretical study

The hydroxylammonium ionic liquids (ILs) falling within the category of protic ionic liquids (PILs) have garnered attention from researchers, owing to their outstanding solubility properties. A one-step method was employed to synthesize a series of ethanolamine ILs. The thermodynamic properties of the ILs, including surface tension, density, and electrical conductivity, were measured across varying temperatures. Essential parameters such as thermal expansion coefficient, molecular volume, surface entropy, and surface energy were estimated using empirical equations. In order to elucidate the intermolecular interactions within the ethanolamine carboxylate ILs, the sigma profiles of ILs were determined using COSMO-RS. It was observed that the ethanolamine cation has a strong potential as a H-bond donor, while the carboxylate anion demonstrates significant capability as a hydrogen bond acceptor. By DFT calculations, it was observed that the NH in the ethanolamine cation can form H-bonds with the oxygen atom in the carboxylate anion.

A non-enzymatic flexible and wearable sensor based on thermal transfer printing technology for continuous glucose detection in sweat

Non-invasive, flexible wearable sensors are an important method to continuously measure glucose in sweat for diabetes and human health monitoring and management. However, how to create an alkaline environment at any time so that CuO based sensors can be applied to wearable devices to detect sweat glucose while finding a way to efficiently and quickly produce the sensors in small batches have been a challenge. Herein, we report a non-enzymatic thermal transferred flexible and wearable sensor based on CuO/CaTiO3 for continuous glucose detection in sweat. The sensor is manufactured using thermal transfer printing technology, which offers advantages like low cost, ease of operation, and rapid small batch production. CuO is known for its excellent electrocatalytic activity, making it a suitable candidate for glucose oxidation. Meanwhile, CaTiO3 particles provide a large specific surface area, good biocompatibility, and electrical conductivity, which enhance the electron transfer rate during detection and broaden the linear range of glucose detection. Specially designed NaOH/Nafion/PEO blend film make the measurements always in a strong alkali environment without any pretreatment and preparation. The synthesized material with this as-prepared flexible and wearable sensor exhibits superior performance towards glucose monitoring, such as high sensitivity of 487.3μA mM−1 cm−2 with limit of detection(LOD) 0.75 μM, wide dynamic linear range from 0.01 mM to 2 mM and fast response time of less than 0.1 s. Additionally, the proposed sensor also exhibited excellent biocompatibility, selectivity, reproducibility and flexibility, as well as good stability with about 88 % of its initial activity after 5 weeks’ storage and it has been successfully applied for the detection of glucose concentration in human sweat real samples. This research contributes to the development of flexible and wearable sensors for non-invasive sweat diagnostics, enabling continuous glucose monitoring for various applications in healthcare and wellness.

Engineering multifunctionality graphene-based nanocomposites with epoxy-silane functionalized cardanol for next-generation microwave absorber

As technology advances, the demand for effective microwave-absorbing materials (MAM) to mitigate electromagnetic wave interference is growing. Two-dimensional (2D) materials are increasingly favored across various fields for their high specific surface area, electrical conductivity, low density, and dielectric loss properties. This study presents lightweight nanocomposites composed of graphene nanoplatelets blended with epoxy resin (ER) and cardanol with silane-functionalized (SFC) as a toughening agent. The resulting nanocomposites exhibit a high surface roughness of 130 nm and an enhanced hydrophobicity, as evidenced by a high contact angle. Notably, the ER/SFC/GNP sample at 3 wt% (0.075 g) achieves a minimum reflection loss value of −18 dB at a thickness of 10 mm, indicating improved impedance matching and enhanced dielectric loss capability. The increasing damping factor ratio to approximately 0.95 further augments the reflection loss performance. The research aims to develop cost-effective, efficient, lightweight graphene-based nanocomposite absorbers.

Synthesis and Characterization of Polyaniline/CuO Nanocomposites with Various Temperature

Polyaniline (PANI) metal oxide composites are known for their high electrical conductivity, environmental stability, and enhanced mechanical strength, making them valuable in applications such as sensors, batteries, and electromagnetic shielding. This study focuses on synthesizing and characterizing PANI/CuO nanocomposites to examine their structural, morphological, and functional properties at different synthesis temperatures. By integrating the conductive polymer PANI with copper oxide (CuO), a p-type semiconductor with a narrow band gap, the material’s capabilities are significantly enhanced. The oxidative polymerization of aniline, the process by which PANI is formed, requires precise control of oxidizing agents and reaction conditions, as these factors directly affect the polymerization, conductivity, and overall properties of the resulting nanocomposite. The PANI/CuO nanocomposites were synthesized at three different temperatures: 10℃, 25℃, and 50℃, to determine how temperature affects their characteristics. Fourier Transform Infrared (FTIR) spectroscopy and Scanning Electron Microscopy (SEM) were employed to analyze these nanocomposites. FTIR results revealed shifts in the quinoid and benzenoid rings, indicating hydrogen bonding between the NH group of PANI and the CuO surface, which accelerates charge transfer. The SEM analysis showed that while pure PANI exhibits a uniform globular morphology, the PANI/CuO nanocomposites display a nanorod morphology. These morphological differences impact the surface area and electrical conductivity of the composites, highlighting the significance of temperature in tailoring the material's properties for specific applications.

Impact of CNT assimilation on binary MoO2/MoS2 hybrid for enhanced cyclic stability during charging-discharging process

Cyclic stability is a crucial metric for assessing the service lifespan of supercapacitors, as it determines the retention capacity of the electrode material. This study demonstrates the significant impact of Carbon Nanotubes (CNT) on enhancing the cyclic stability of a binary hybrid MoO2/MoS2 (MOS) electrode material, thereby improving supercapacitor performance and durability. The combination of MoO2 and MoS2 enhances capacitance due to their high surface area and electrical conductivity. Introducing CNTs into MOS significantly enhances cyclic stability and provides a crucial pathway for electrolyte ions during charging-discharging cycles, despite a minor compromise in conductivity and energy efficiency. This trade-off is justified by the substantial improvement in overall performance and durability. The materials were synthesized and deposited on Nickel foam via a hydrothermal route without any binding agent. Electrochemical tests showed specific capacitances of 2617 F/g for MOS and 2052 F/g for MOSC at a current density of 1 A/g. The MOSC system exhibited a 41.4 % increase in cyclic stability after 2000 cycles. Additionally, a symmetric coin cell device fabricated with the MOSC material demonstrated a maximum energy density of 153.41 mWh/kg and a power density of 3 kW/kg at a current density of 0.05 A/g, with a capacitive retention of 74.05 %. This underscores the potential of MOSC as a scalable electrode material for industrial energy storage applications.

Optimizing oxygen transport properties in Al-substituted La0.5Sr0.5Co0.8Fe0.2-xAlxO3-δ (x = 0–0.20) perovskites

In recent years, there has been a surge in the investigation of perovskite-type complex oxides, with a particular focus on La1-xSrxCo1-yFeyO3, renowned for their exceptional mixed ionic-electronic conducting (MIEC) properties. La0.6Sr0.4Co1-yFeyO3 compositions have prominently emerged in this research domain. The hypothesis of enhancing redox stability and mitigating oxygen variations by incorporating trivalent aluminum (Al3+) into the B-site of perovskite structures has gained attention. In this study, single-phase La0.5Sr0.5Co0.8Fe0.2-xAlxO3-δ (x = 0–0.20) perovskite oxides were synthesized using the solution combustion technique. The physicochemical properties of the synthesized materials were thoroughly characterized, including their morphology, thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) analysis, oxygen nonstoichiometry, and electrical transport properties. Results revealed lattice parameter variations associated with oxygen nonstoichiometry and B-site cation size, exhibiting a decline up to x = 0.10 followed by an increase. Al-substitution significantly influenced surface morphology, oxygen nonstoichiometry, and electrical conductivity. Notably, La0.5Sr0.5Co0.8Fe0.1Al0.1O3-δ displayed lower electrical conductivity (676 S cm−1 at 300 °C) among the studied oxides. Oxygen nonstoichiometry had a significant impact on oxygen transport parameters, with these perovskites demonstrating improved chemical diffusion coefficient, Dchem (5.5 × 10-5 cm2 s−1), and the oxygen surface exchange coefficient, Kchem (2.32 × 10-5 cm s−1) at 900 °C, suggesting its potential as an oxygen transport membrane. These findings underscore the promising role of Al-substituted perovskite oxides in various advanced applications.

Exploring Electrochemical Sensing for Fungicide Detection: Utilization of Newly Synthesized Oligomers.

The determination of thiabendazole is crucial for ensuring food safety, environmental protection, and compliance with regulatory standards. Accurate detection helps prevent harmful exposure, ensuring the safety of agricultural products and safeguarding public health. Therefore, this study investigates the electrochemical sensing capabilities of newly synthesized oligo 3-amino-5-mercapto-1,2,4-triazole (oligo AMTa) using hydrogen tetrachloroaurate (III) (HAuCl4) as an oxidizing agent at room temperature for thiabendazole (TBZ) detection, employing a simple electrode fabrication process. The prepared oligo AMTa was thoroughly characterized using UV-visible spectroscopy, scanning electron microscopy (SEM), Energy Dispersive X-ray Analysis (EDAX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), high-resolution mass spectroscopy (HR-MS), and Fourier-transform infrared spectroscopy (FT-IR) to confirm its oligomerization structure and properties. The IR spectrum of oligo AMTa reveals a new peak at 1449 cm-1, indicating the conversion of -NH2 groups to -N=N- groups during oligomerization, unlike AMTa. Additionally, the disappearance of the -SH group peak at 2615 cm-1 in oligo AMTa suggests an S-S linkage involvement in the oligomerization process. In the oligo AMTa XPS spectrum, the presence of C=N is displayed by a small peak at 287.3 eV, and oligomerization via -NH and N=N is confirmed by the lack of a 284.0 eV peak for C-C or C=C. Gold nanoparticle formation is not demonstrated by the 84.8 eV peak, which implies that the gold atom is not in the Au0 state. The HR-MS spectrum of oligo AMTa shows a peak at m/z 564.08, indicating a chain of five monomers, and another peak at m/z 435.03, confirming the presence of a tetrameric form of AMTa. After that, the GC electrode was directly linked to the oligo AMTa by the potentiodynamic method. SEM, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) were all employed to confirm the fabrication of oligo AMTa. The SEM image illustrates the formation of a particlelike structure with a uniform size of the oligomer after cycling in 0.1 M H2SO4. After electrocycling, the size of the oligomer was reduced from 2.6 μm to 30 nm. The oligo AMTa-modified electrode possesses the highest electroactive surface area and electrical conductivity due to several key factors. First, the presence of amino (-NH2) and thiol (-SH) functional groups in AMTa enhances the surface coverage and density of electroactive sites, increasing the electroactive surface area. Additionally, the conjugated structure of AMTa facilitates efficient electron transfer, resulting in enhanced electrical conductivity compared to unmodified electrodes. Eventually, the electrochemical oxidation of TBZ occurred using the fabricated electrodes. The GC/oligo AMTa electrode exhibited a four-fold increase in oxidation current for TBZ compared to unmodified GC electrodes. This enhancement is due to the improved surface properties from the oligo AMTa modification, which significantly boosts TBZ adsorption through strong interactions like hydrogen bonding and π-π stacking. These interactions, along with the increased surface area and catalytic properties, facilitate effective electron transfer, resulting in a higher oxidation current. As an outcome, the film was employed to determine the sensitivity level of TBZ, and a LOD of 1.8 × 10-11 M (S/N = 3) was found. The straightforward method's practical utility was proven by measuring TBZ in tap water, water spinach, and pear juice samples. The comprehensive characterization of oligo AMTa provided insights into its interaction mechanisms with thiabendazole, contributing to the development of a reliable, cost-effective, and efficient sensor.

Amorphous NiB layer deposition and piezoelectric field assisted for efficient photocatalytic degradation of Sb2S3

The poor surface charge reaction efficiency and electrical conductivity limit the further application of Sb2S3 in photocatalytic degradation of pollutants. An amorphous NiB layer was deposited on the surface of Sb2S3 by photo-assisted electrodeposition, and the presence of the NiB layer accelerated the charge transport and catalytic reactivity, which greatly enhanced the degradation ability. The photocurrent density of NiB-Sb2S3 was about 0.12 mA/cm2, which was 6 times of that of pure Sb2S3. After increasing the applied mechanical site by ultrasonication, the photocurrent of NiB-Sb2S3 was further increased to 0.19 mA/cm2, which was almost 9.5 times that of pure Sb2S3 under photocatalytic conditions alone. The catalytic kinetic curves show that the degradation rate of RhB by NiB-Sb2S3 under piezoelectric-photocatalytic conditions is significantly increased, being 11.48 times of the degradation rate of Sb2S3 under photocatalytic conditions. The detailed experimental data indicate that the amorphous NiB layer not only changes the electronic structure of the catalyst surface, but also increases the number and activity of the catalyst active sites, and reduces the chance of electron and hole recombination after photoexcitation. The introduction of an applied piezoelectric field provided a driving force for carrier migration to the catalyst surface, which further improved the separation ability. This study provides a new strategy to further improve the photocatalytic degradation.

The electrochemical mechanism of biochar for mediating the product ratio of N2O/(N2O + N2) in the denitrification process

The biochar electrochemical properties and surface functional groups significantly impact N2O production and reduction during denitrification process. However, its effects on N2O emissions during the denitrification process and its electrochemical mechanisms remain unclear. The study examined the impact of pristine and oxidized biochar combined with two types of nitrogen fertilizers on the N2O/(N2O + N2) ratio and N2O emissions in an incubation experiment with seven treatments: (1) CK (no application of chemical fertilizer); (2) N1 (applying (NH4)2SO4); (3) N1B ((NH4)2SO4 + pristine biochar); (4) N1BO ((NH4)2SO4 + oxidized biochar); (5) N2 (applying KNO3); (6) N2B (KNO3 + pristine biochar); (7) N2BO (KNO3 + oxidized biochar). The study found that in comparison with applying nitrogen fertilizer alone, combining pristine biochar decreased soil N2O concentration by 7.1 %–85.8 %, while combining oxidized biochar increased it by 15.7 %–125.6 %. Applying pristine biochar reduced N2O/(N2O + N2) ratio by 10.4 %–86.2 %, whereas applying oxidized biochar increased it by 12.9 %–121.6 %. The application of pristine biochar increased the nosZ gene abundance and decreased the (nirS + nirK)/nosZ ratio, which contributed to reducing N2O to N2. Compared with oxidized biochar, the oxygen-containing functional groups of pristine biochar decreased by 46.6 %, and it possessed a higher specific surface area (23.01 m2 g−1) and electrical conductivity (0.003 mS cm−1). The correlation analysis showed that DOC and inorganic nitrogen were the key environmental factors affecting N2O emissions. Additionally, the electrical conductivity, specific capacitance, and oxygen-containing functional groups of the biochar were identified as the main factors driving N2O emissions. The SEM analysis suggested that the indirect influence of biochar electrochemical properties on N2O emissions was greater than its direct influence. Our work provides fresh perspectives on reducing soil N2O emissions and establishes a theoretical foundation for the subsequent preparation of biochar materials with enhanced N2O reduction capabilities.

From Farm to Fork: Enhancing Agricultural and Food Safety Monitoring with Laser-Engineered Graphene Sensors

In the critical fields of precision agriculture and food safety, the demand for accurate and sensitive monitoring tools for fertilizers, pesticides, and food-borne pathogens cannot be overstated. Our collaborative research with commercial entities seeks to overcome the challenges faced by current electrochemical ion-selective, enzymatic, and immunosensors, which often fall short in selectivity, stability, and sensitivity, particularly under field conditions. We showcase the tunable properties of Laser-Induced Graphene (LIG) – such as surface wettability, roughness/area, and electrical conductivity – and their instrumental role in enhancing the commercial viability of these sensor technologies.We demonstrate the conversion of hydrophilic Laser-Induced Graphene (LIG) to a near-superhydrophobic state using an innovative dual-laser process in ambient conditions. This method intricately sculpts the surface into micro and nanoscale structures reminiscent of a lotus leaf, resulting in nearly superhydrophobic characteristics. By modifying the laser's power, speed, and fluence, we can also fine-tune the electroactive surface area and electrical conductivity, significantly impacting sensor functionality. For solid contact ion-selective electrodes (SC-ISEs), enhancing the LIG surface with high hydrophobicity prevents water layer accumulation at the ion-selective membrane and electrode interface. This design expels water from within the membrane, fosters stronger membrane-electrode adhesion, and consequently, diminishes signal interference. Such improvements are instrumental in boosting the sensor's accuracy and extending its operational lifespan. In contrast, a hydrophilic LIG with a large surface area enhances catalytic efficiency and allows more biorecognition agents to adhere to its surface, thereby amplifying the sensitivity of enzymatic pesticide sensors. Lastly, a flat, hydrophilic LIG surface ensures an even distribution of antibodies, which enhances the performance of sensors detecting foodborne pathogens.These modifications to LIG and the resulting sensors have substantial commercial potential. We have developed ions sensors for nitrate, ammonium, potassium, calcium, and magnesium have demonstrated near-Nernstian sensitivities, extensive sensing ranges across four orders of magnitude, and the ability to detect concentrations as low as 1 ppm in soil and water samples. These sensors are currently being integrated into commercial soil moisture and temperature probes for monitoring in farm fields. The pesticide sensing capability of the sensor can reach an extremely low picomolar detect limit for organophosphates, the nanomolar regime for neonicotinoids, and micromolar regime for glyphosate in surface waters. These sensors are currently being interfaced with LIG-based mist/fog harvesting devices to monitor pesticide and spray drift in farm fields. Finally, the LIG-based Salmonella sensors are capable of monitoring bacteria such as Salmonella to about 10 CFU/mL in actual food matrices such as chicken broth without the need for sample preconcentration or costly lab analyses.This research forges innovative avenues in agriculture and food safety monitoring, laying the groundwork for mass production of efficient and economical sensors. We believe this technology will revolutionize field monitoring, significantly advancing sustainable agriculture and improving public health safety. Figure 1

Graphene Supported Silicon Nanocomposites As Anode for Lithium-Ion Batteries

This work indicates Silicon/Grphene (Si/G) nanocomposites anode on the performance in lithium-ion batteries (LIBs).The self-assembled graphene aerogel and silicon (Si/G) anode materials with some surface defects have been successfully prpared by hydrothermal synthesis using chemically modified graphene oxide and commercial Si nanopowder (about 50 nm) as precursor. The morphologies and textural properties of as-obtained Si/G were investigated by scanning electron microscopy, X-ray photoelectron spectroscopy, and other sturucture techniques. The surface defects and electrical conductivities of Si/G can be controlled by adjusting the amount of Si nanopowder. The results indicate that Si/G with Si amount of half exhibits excellent stability and reversible capacity and superior rate capability with excellent cycling stability. It is demonstrated that the 3D porous network with increased defect density, as well as the considerable electrical conductivity, results in the excellent electrochemical performance of the as-made Si/G anodes in LIBs.