Flexible pressure sensors (FPSs) are gaining widespread attention for their potential applications in areas such as human kinematic studies and human–machine interfaces. The development of sustainable, low-cost, easy-to-manufacture piezoresistive composites that ensure reliability in FPS fabrication has remained a consistent focus. In this study, we present a facile approach for preparing hemp fabric-based piezoresistive composites to fabricate cost-effective FPSs. The hemp fabric is impregnated with acid-treated multi-walled carbon nanotubes (MWCNTs) through a simple dip-and-dry process. With an optimized MWCNT loading of 1.33 wt

Achieving long-term stability, a broad sensing range, and scalability in the fabrication of flexible pressure sensors (FPS) remains a significant challenge. In this work, we introduce a piezoresistive FPS fabricated by dip-coating sulfonitric acid-treated multiwalled carbon nanotubes (MWCNTs) and poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) onto crepe bandage fabric, a rarely explored material for FPS fabrication. The synergistic combination of MWCNTs and PEDOT:PSS ensures strong pi-pi interactions and stable electrical conductivity. The optimized sensor exhibits notable sensitivities of 0.044 kPa(-1), 0.0023 kPa(-1), and 0.0006 kPa(-1) across pressure ranges of 0-12 kPa, 12-75 kPa, and 75-200 kPa, respectively, with a low detection limit of 6 Pa, rapid response and recovery times (237 and 63 ms), and durability exceeding 8000 cycles. Applications such as motion monitoring and two-dimensional pressure mapping are demonstrated.

Photocatalytic technology is advancing rapidly, offering enormous potential for fostering a sustainable future. Its ability to enable clean energy production through eco-friendly applications has made it a key component of global sustainability efforts. Layered double hydroxides (LDHs) have emerged as promising photocatalysts owing to their unique structural, electronic, and chemical properties. These qualities place LDHs at the forefront of addressing emerging energy and environmental challenges, further strengthening their importance in photocatalytic applications. The various compositions of LDHs, achieved through the selective variation of metal cations (M2+ and M3+), enable precise bandgap engineering to optimize light absorption. Furthermore, LDHs exhibit remarkable stability under ultraviolet and visible light, ensuring their durability over time. Their lightharvesting and catalytic activities are further enhanced when integrated with other materials, thereby expanding their application scope. These synergistic properties enable LDHs to excel in photocatalytic processes aimed at clean and sustainable energy generation. This review emphasizes LDH-based heterostructures for photocatalytic energy conversion, particularly in hydrogen (H2) production and carbon dioxide (CO2) reduction, highlighting their considerable potential to drive the development of a durable LDH photocatalytic system for future sustainable energy solutions is also presented.

Wearable sensors integrated with the Internet of Things (IoT) are continually researched and developed due to their ever-expanding applications in various fields, including personalized healthcare, human-machine interfaces, and soft robotics. Flexible pressure sensors (FPSs) stand out for their critical role in capturing motions using various mechanisms. Piezoresistive-type FPSs, which employ single-layer fabrics as substrates, rarely achieve significant sensitivity beyond the very low-pressure range, thereby failing to cover a wide range of motion signals with appreciable sensitivity. Despite several reports that have utilized novel configurations, sensing material combinations, and fabrication steps, a strong demand remains for high-performance FPSs integrated with IoT. In this work, we present a three-layer fabric-based piezoresistive FPS, with a substrate consisting of medical gauze sandwiched between two layers of silk/cotton blend fabric. Acid-treated carbon black (CB) and multiwalled carbon nanotubes (MWCNTs) are used to coat the fabric blend in a simple dip-and-dry process. The biodegradable silk/cotton blend-based pressure sensor demonstrated notable sensitivities of 0.471 kPa(-1), 0.0134 kPa(-1), and 0.0012 kPa(-1) across the pressure ranges of 0-1 kPa, 1-11 kPa, and 11-62 kPa, featuring a response time of 126 ms, a relaxation time of 46 ms, and excellent cycle stability, enduring 20,000 cycles. Capable of monitoring various bending motions and other signals, this MWCNT/CB/silk/cotton blend-based FPS, along with a wireless transmission system to send signals to a cloud accessible by authorized healthcare professionals, significantly advances next-generation devices in healthcare and diagnostics.

Flexible pressure sensors (FPSs) have garnered significant interest among researchers focusing on wearable electronics for motion recognition, health care, rehabilitation therapy, athletic performance monitoring, and more applications. Recently, fabrics known for their flexibility and comfort have become popular substrates for fabricating various flexible sensors. Of these flexible sensors, piezoresistive devices are favored for their simplicity and notable sensitivity to physical movements. This study presents a fabric composite created by coating a viscose staple fiber/linen blend with functionalized conductive carbon black (CB) using a simple drop-coating method and evaluates its pressure-sensing performance. The FPS with optimum CB content exhibited sensitivities of 41.1 kPa-1 and 1.4 kPa-1 in the pressure ranges of 0-1 kPa and 1-20 kPa, respectively. With a low detection limit of 10 Pa, a response time of 16 ms, a relaxation time of 63 ms, durability exceeding 5,400 cycles, and stable performance in various ambient conditions, the FPS has exhibited potential for applications in bending motion monitoring and information transmission.

Developing cost-effective bifunctional electrocatalysts that operate at high current densities is essential for large-scale water electrolysis applications. Metal phosphide-based nanostructures and nanocomposites are among the most efficient electrocatalysts that can be involved in both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, we have synthesized high-performance bifunctional hetero-interfacial structured nickel phosphide composites by a simple hydrothermal reaction. Through distinct configurations, Ni2P/Ni12P5 (NNP) tailored with 3 wt% single-walled carbon nanotubes (SWCNT) and integration of Fe3O4 with SWCNT/Ni2P/Ni12P5 heterostructures significantly delivered a high current density in an alkaline medium. The in-situ growth of Fe3O4 on SWCNT-NNP enhanced the electrical conductivity and dissociation of the water molecule, thereby enhancing the HER and OER performance of the catalyst in an alkaline medium. The HER and OER of 4 h Fe-3wt% SWCNT-NNP reached a current density of 100 mAcm(-2) at an overpotential of 301 and 240 mV dec(-1), respectively. The overall water-splitting of 4 h Fe-3wt% SWCNT-NNP showed a cell voltage of 2.17 V to reach the current density of 100 mAcm(-2). The fabricated water-splitting device showed a high stability of 98.6 % after 30 h of reaction at 100 mAcm(-2). The enhanced performance of these bifunctional catalysts paves the way for the development of highly durable electrocatalysts for large-scale applications.

Reduced graphene oxide (RGO) was functionalized with nitrogen-enriched sulfur-containing groups via a facile and cost-effective hydrothermal approach to enhance the electrochemical performance of RGO nanosheets. The crystallinity, morphology, and chemical composition of obtained nitrogen-enriched sulfur-functionalized reduced graphene oxide (NESRGO) was investigated using X-ray diffraction, Raman spectroscopy, field-emission scanning electron microscopy, and X-ray photoelectron spectroscopy. The electrochemical investigation of NESRGO with higher electronegativity and improved electrical conductivity yielded a superior oxidation current of 52 mu A towards uric acid (UA) than nitrogen sulfur-functionalized reduced graphene oxide (NSRGO) (30 mu A) and RGO (21 mu A). The NESRGO-modified electrode showed high sensitivity (826.25 mu A mM-1 cm-2), a detection limit of 4 mu M, and good stability (relative standard deviation of 3.69%). Moreover, the high selectivity of the developed UA sensor in the presence of other electroactive interferents and excellent recovery rates between 99.29% and 110.40% in human serum demonstrated the applicability of the sensor in clinical diagnosis. Finally, the NESRGO-modified carbon cloth electrode applied as a supercapacitor exhibited a specific capacitance of 70.23 F g-1 and excellent cycle stability, with 109.7% retention over 2,500 cycles. The results highlight the NESRGO's potential in UA sensing and energy storage devices. A hydrothermal approach was used to functionalize the reduced graphene oxide (RGO)Nitrogen/sulfur groups incorporated on RGO enhance the electrocatalytic propertyNitrogen-enriched sulfur functionalized RGO (NESRGO) was applied to sense uric acidThe sensor displayed a detection limit of 4 mu M and and a sensitivity of 826.25 mu A mM-1 cm-2The supercapacitor developed using NESRGO achieved a capacitance retention of 109.7%

Bimetallic metal-organic frameworks (MOFs) show promise for electrochemical applications despite challenges posed by their low electrical conductivity and stability. Here, we introduce bimetallic (NiCu)-MOFs anchored on nitrogen-doped graphene nanoribbons (NGNRs) to enhance conductivity and stability. Experimental investigations on a (NiCu)-MOFs/NGNRs-modified glassy carbon electrode revealed a maximum oxidation current of 148 mu A and a minimum charge transfer resistance of 4.01 k Omega , indicating excellent electrocatalytic activity. We further evaluated the modified electrode's performance for glucose sensing using cyclic voltammetry and chronoamperometry techniques, achieving a notable oxidation peak current of 519 mu A, which confirms its superior electrochemical activity. The developed enzyme-free glucose sensor exhibits a wide dynamic range ( 1.16 mu M - 4.5 mM), high sensitivity ( 181.67 mu A mM(-1) cm(-2)), a short response time (3 s), and a low detection limit (825 nM). Moreover, the proposed sensor exhibits better long-term stability, with a 96% amperometric response after seven days, and excellent selectivity in the presence of other interferents, such as ascorbic acid, dopamine, uric acid, and sucrose. This demonstrates its efficacy in human serum and non-alcoholic beverages.

In this work, a three-dimensional microflower-structured mixed metal oxide (MMO) electrocatalyst composed of NiO, Co3O4, and Fe3O4 was synthesized to enhance overall water splitting efficiency in alkaline media. The hetero-interfacial catalyst was developed by modifying Ni and Co oxides with Fe3O4, resulting in improved electrocatalytic efficiency for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). The present synthesis employed electrodeposition combined with 2-methylimidazole (MeIM)-assisted synthesis, which enabled the incorporation of Fe3O4 and preserved the 3D flower-like morphology. This approach offered better interfacial integration and structural control. Structural characterization using XRD, FESEM, and XPS confirmed the successful formation of NiO/Co3O4/Fe3O4 heterostructures (NiCo-Fe-2) with strong electronic interactions, mixed-valence states, and a porous nanosheet architecture. XPS analysis revealed a strong electronic interaction among the oxides of Ni, Co, and Fe species, contributing to an enhanced redox behavior. NiCo-Fe-2 exhibited superior OER activity, requiring only 1.465 V to reach 10 mA cm- 2 with a Tafel slope of 56 mV dec- 1. For HER, it showed enhanced performance with an overpotential of 203 mV at the same current density. The material has achieved high-current densities, confirming its suitability for high-rate water electrolysis. Electrochemical impedance spectroscopy and electrochemical surface area (ECSA) measurements showed a low charge-transfer resistance and a large ECSA, indicating favourable charge kinetics and abundant active sites. The highly integrated 3D microflower network with edge-rich active sides exhibited an enhanced ECSA of 125.75 cm2. The stability was assessed using the chronopotentiometry technique, where the catalyst maintained a stable potential under a constant current of 50 mA cm-2, providing information on the structural integrity and electrochemical durability of the NiCo-Fe-2.

In the present work, we report on developing an electrochemical dopamine sensor using a novel material of nitrogen-rich sulfur dual-doped reduced graphene oxide (N-rich SRGO). Nitrogen and sulfur heteroatoms were incorporated into graphene sheets through a one-step, cost-effective hydrothermal approach to synthesize N-rich SRGO. Experimental investigations were carried out to compare the electrochemical properties of N-rich SRGO with nitrogen sulfur-doped reduced graphene oxide (NSRGO), nitrogen-doped reduced graphene oxide sheets (NRGO), and reduced graphene oxide (RGO) by modifying the glassy carbon electrode. Electrochemical studies demonstrated that N-rich SRGO exhibited a notably higher oxidation current (345 mu A) compared to NSRGO (219 mu A), NRGO (173 mu A), and RGO (160 mu A). We developed a dopamine sensor by utilizing the superior chemical reactivity and enhanced charge carrier density of the proposed N-rich SRGO-modified electrode. Experimental results reveal a high sensitivity of 142 mu A/mM, with a limit of detection of 9.3 mu M and a wide dynamic range of 150- 350 mu M. This N-rich SRGO-based sensor displayed excellent repeatability and selectivity, even in the presence of other electroactive interferents, showcasing its potential for practical applications.

Photocatalytic hydrogen production is recognized as a promising approach to produce greener hydrogen. The development of next-generation photocatalytic materials aims to enhance photocatalysis efficiency. Perovskite, a third-generation photocatalytic material, has gained interest in photocatalytic water splitting due to its optical stability, structural flexibility, bandgap tunability, and charge transfer efficiency. However, the perovskites are not able to achieve the targeted efficiency. Perovskite-based Z-scheme heterojunction photocatalysts can enhance efficiency. This review gives special attention to types and the formation of Z-schemes. In particular, photocatalysts involved in all-solid-state and direct Z-scheme for photocatalytic hydrogen production have been discussed.

Flexible pressure sensors, with prominent applications in healthcare, human-computer interface, and motion monitoring, have garnered significant interest among researchers in recent times. Melamine foam (MF), valued for its porous structure and accessibility, is a preferred material for flexible pressure sensors. Various electrically conducting nanomaterials are incorporated into these foams to realize piezoresistive flexible sensors. Carbon nanotubes (CNTs), one of the filler materials used in these sensors, suffer from the issues of agglomeration and uneven dispersion when used as a single filler, which significantly affects the sensing properties of the piezoresistive foam-based sensors. Covalent functionalization, such as nitrogen doping, effectively addresses these issues and modifies the properties of carbon nanotubes (CNTs) to enhance their performance in various applications. In the present work, we have prepared a nitrogen-doped CNT (N-CNT) using a simple hydrothermal method and fabricated piezoresistive flexible pressure sensors using N-CNT/MF by facile dip coating method. The 4wt% N-CNT/MF pressure sensor worked in the 0-35 kPa range and showed a sensitivity of 0.172 kPa -1 in the 0-4 kPa range. With a low detection limit of 18 Pa, a response time of 0.4 s, and a relaxation time of 0.46 s, the sensor’s performance was stable for more than 1800 cycles. The sensor was tested for monitoring wrist, elbow, finger, and knee bendings and finger pressing, demonstrating its applicability in human motion monitoring applications.

The integration of electronic functionalities into textiles has been under extensive research as its application is witnessed in various fields, including sensing, energy generation, storage, displays, and interfaces. Textiles endowed with flexibility, comfort, lightweight, and washability have been tested as reliable base materials to implement various physical sensors, of which strain and pressure sensors have shown great potential in applications such as healthcare, fitness tracking, and human-machine interaction. Piezoresistive physical sensors have considerable advantages over capacitive and piezoelectric sensors made of textiles. Apart from fibers, yarns, and threads, two-dimensional textile stripes occupy a significant share as substrates in these sensors. This review article discusses the recent progress of 2D textile-based piezoresistive strain and pressure sensors. It covers the latest works in this domain, focusing on different textile choices, conductive material combinations, fabrication methods, additional functionalities like heating, features like hydrophobic properties, and various applications, with tabulations of key performance metrics. For researchers seeking an update on the state of the field, this review would be helpful as it offers insights into trends for further research and product development aimed at meeting the demands of advanced healthcare and other applications.

Ovarian cancer (OC) is a deadly disease with a high mortality rate, primarily due to its often asymptomatic nature in early stages and the absence of effective screening methods. Conventional imaging methods have several drawbacks, such as difficulty in detecting small tumors, challenges in differentiating between benign and malignant tumors, dangerous radiation exposure, high cost, low sensitivity, and low specificity in detecting early-stage malignancies. On the other hand, 2D nanomaterials-based electrochemical biosensors present novel opportunities for early detection of ovarian cancer biomarkers, leveraging their unique properties such as high surface-to-volume ratio and excellent electrical conductivity. These materials enhance sensor sensitivity and selectivity, enabling the detection of biomarkers at ultra-low concentrations, thus improving diagnostic accuracy. Their compatibility with miniaturization further facilitates the development of portable, point-of-care devices, revolutionizing early screening efforts in ovarian cancer detection. This review paper overviews recent advancements in OC biomarker detection using 2D nanomaterials-based electrochemical biosensors. A detailed discussion is presented on the electrochemical detection of carbohydrate antigen 125 (CA125), mucin 1 (MUC1), and human epididymis protein 4 (HE4) biomarkers regarding sensing materials, sensing approach, analytical technique, and performance characteristics like limit of detection and linear range. Other OC biomarkers such as SKOV3, breast cancer gene 1 (BRCA1), stress-induced phosphoprotein 1 (STIP1), and flavin adenine dinucleotide are also briefly discussed. Finally, the review discusses the difficulties and future outlooks of diagnosing OC via an electrochemical sensing approach. The present review article emphasizes the application of 2D nanomaterials in the early diagnosis of ovarian cancer through an electrochemical sensing approach.

The solutions for environmental remediation and renewable energy generation have intensified the exploration of efficient photocatalytic materials. Recently, the composites of g-C3N4and MXene have gained considerable interest for their potential applications in photocatalysis. In the g-C3N4-MXene composite, the g-C3N4possesses unique physical, chemical, and optical properties to increase visible light absorption. At the same time, MXene improves conductivity, adsorption of reactant molecules or the active sites, and charge transfer properties. Combining the unique physico-chemical properties of MXene and g-C3N4, the resulting composite exhibits superior photo-responsive behavior and is critical in photocatalytic reactions. Furthermore, the g-C3N4-MXene composite exhibits stability and recyclability, making it a promising candidate for sustainable and scalable photocatalytic material in environmental remediation. This review offers an in-depth analysis of the development and design of g-C3N4-MXene composites through diverse synthesis procedures and a comprehensive analysis of their application in carbon dioxide (CO2) reduction, photocatalytic degradation, water splitting processes, mainly hydrogen (H2) generation, H2O2production, N2fixation, and NOxremoval. The charge transfer mechanism of g-C3N4-MXene composite for photocatalytic application has also been discussed. This review provides insights into the photocatalytic capabilities of g-C3N4-MXene composites, showing their potential to address current environmental challenges and establish a robust foundation for sustainable energy conversion technologies.

Monocrystalline bulk silicon with doped impurities has been the widely preferred piezoresistive material for the last few decades to realize micro-electromechanical system (MEMS) sensors. However, there has been a growing interest among researchers in the recent past to explore other piezoresistive materials with varied advantages in order to realize ultra-miniature high-sensitivity sensors for area-constrained applications. Of the various alternative piezoresistive materials, silicon nanowires (SiNWs) are an attractive choice due to their benefits of nanometre range dimensions, giant piezoresistive coefficients, and compatibility with the integrated circuit fabrication processes. This review article elucidates the fundamentals of piezoresistance and its existence in various materials, including silicon. It comprehends the piezoresistance effect in SiNWs based on two different biasing techniques, viz., (i) ungated and (ii) gated SiNWs. In addition, it presents the application of piezoresistive SiNWs in MEMS-based pressure sensors, acceleration sensors, flow sensors, resonators, and strain gauges.

A large surface area is an imperative parameter for electrocatalytic materials applied in electrochemical devices. In the present work, Ni nanoparticles were synthesized by hydrothermal method using three surfactants: sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB), and polyvinyl pyrrolidone (PVP) and two base media, i.e., sodium hydroxide (NaOH) and ammonium hydroxide (NH4OH). We investigated the effects of different surfactants and base mediums on Ni nanoparticles' crystallite size, particle size, and surface area. Experimental results revealed that Ni nanoparticles with smaller particle sizes (50-90 nm) and large surface area (28.4-64 m2/g) were obtained when NaOH was used as the base medium with all surfactants. Further, a high specific capacitance of 417 F/g, minimum charge transfer resistance of 490 ohm, and 91 % capacitance retention demonstrated that Ni nanoparticles obtained using PVP in NaOH could be applied as potential working electrode material in enhancing the performance of supercapacitor devices.

Nanowire-based technological advancements thrive in various fields, including energy generation and storage, sensors, and electronics. Among the identified nanowires, silicon nanowires (SiNWs) attract much attention as they possess unique features, including high surface-to-volume ratio, high electron mobility, bio-compatibility, anti-reflection, and elasticity. They were tested in domains of energy generation (thermoelectric, photo-voltaic, photoelectrochemical), storage (lithium-ion battery (LIB) anodes, super capacitors), and sensing (bio-molecules, gas, light, etc). These nano-structures were found to improve the performance of the system in terms of efficiency, stability, sensitivity, selectivity, cost, rapidity, and reliability. This review article scans and summarizes the significant developments that occurred in the last decade concerning the application of SiNWs in the fields of thermoelectric, photovoltaic, and photoelectrochemical power generation, storage of energy using LIB anodes, biosensing, and disease diagnostics, gas and pH sensing, photodetection, physical sensing, and electronics. The functionalization of SiNWs with various nanomaterials and the formation of heterostructures for achieving improved characteristics are discussed. This article will be helpful to researchers in the field of nanotechnology about various possible applications and improvements that can be realized using SiNW.

Gd-substituted barium hexaferrite has been synthesized by solid-state ceramic method to explore its X -band (8.2 - 12.4 GHz) absorption and shielding performance. The structural, magnetic, and microwave properties of the synthesized hexaferrite were studied by X-ray diffraction (XRD), micro-Raman spectro-scopy, field emission scanning electron microscopy (FESEM), vibrating sample magnetometer (VSM), and vector network analyzer (VNA). XRD patterns confirmed the hexagonal magnetoplumbite phase formation in all samples. A noticeable red shift in the Raman spectra from 710 to 705 cm-1 and 323-327 cm-1 sug-gested the presence of Fe2+ ions at 4f1 tetrahedral and 12k octahedral sites, respectively. Microstructural studies on as-prepared samples confirm particle size reduction up to 1.86 mu m with Gd substitution. A modest increase in magnetization and remanence value for 20% Gd was noted. Coercivity increased with substitution, whereas the anisotropy field and crystalline anisotropy constant reduced with Gd addition. An overall improvement in shielding efficiency and absorption was noted for Gd-substituted samples. A maximum average shielding efficiency of 16.47 dB and effective absorption of 99.99% was recorded for 10% Gd. Overall, microwave absorbance is improved up to 97% with Gd substitution, which suggests this ma-terial can also work as an absorber in microwave device applications.(c) 2023 Elsevier B.V. All rights reserved.