Sustainable synthesis of spongy-like porous carbon for supercapacitive energy storage systems towards pollution control.

In this study, the fruit of Terminalia chebula, commonly known as chebulic myrobalan, is used as the precursor for carbon for its application in supercapacitors. The Terminalia chebula biomass-derived sponge-like porous carbon (TC-SPC) is synthesized using a facile and economical method of pyrolysis. TC-SPC thus obtained is subjected to XRD, FESEM, TEM, HRTEM, XPS, Raman spectroscopy, ATR-FTIR, and nitrogen adsorption-desorption analyses for their structural and chemical composition. The examination revealed that TC-SPC has a crystalline nature and a mesoporous and microporous structure accompanied by a disordered carbon framework that is doped with heteroatoms such as nitrogen and sulfur. Electrochemical studies are performed on TC-SPC using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. TC-SPC contributed a maximum specific capacitance of 145 F g-1 obtained at 1 A g-1. The cyclic stability of TC-SPC is significant with 10,000 cycles, maintaining the capacitance retention value of 96%. The results demonstrated that by turning the fruit of Terminalia chebula into an opulent product, a supercapacitor, TC-SPC generated from biomass has proven to be a potential candidate for energy storage application.

Recent progress and perspectives of metal organic frameworks (MOFs) for the detection of food contaminants.

Over the past decades, increasing research in metal-organic frameworks (MOFs) being a large family of highly tunable porous materials with intrinsic physical properties, show propitious results for a wide range of applications in adsorption, separation, electrocatalysis, and electrochemical sensors. MOFs have received substantial attention in electrochemical sensors owing to their large surface area, active metal sites, high chemical and thermal stability, and tunable structure with adjustable pore diameters. Benefiting from the superior properties, MOFs and MOF-derived carbon materials act as promising electrode material for the detection of food contaminants. Although several reviews have been reported based on MOF and its nanocomposites for the detection of food contaminants using various analytical methods such as spectrometric, chromatographic, and capillary electrophoresis. But there no significant review has been devoted to MOF/and its derived carbon-based electrodes using electrochemical detection of food contaminants. Here we review and classify MOF-based electrodes over the period between 2017 and 2022, concerning synthetic procedures, electrode fabrication process, and the possible mechanism for detection of the food contaminants which include: heavy metals, antibiotics, mycotoxins, and pesticide residues. The merits and demerits of MOF as electrode material and the need for the fabrication of MOF and its composites/derivatives for the determination of food contaminants are discussed in detail. At last, the current opportunities, key challenges, and prospects in MOF for the development of smart sensing devices for future research in this field are envisioned.

Mesoporous NiO/Ni2O3 nanoflowers for favorable visible light photocatalytic degradation of 4-chlorophenol.

The present study highlights the treatment of industrial effluent, which is one of the most life-threatening factors. Herein, for the first time, two types of NiO (green and black) photocatalysts were prepared by facile chemical precipitation and thermal decomposition methods separately. The synthesized NiO materials were demonstrated with various instrumental techniques for finding their characteristics. The X-ray diffraction studies (XRD) and X-ray photoelectron spectroscopy (XPS) revealed the presence of Ni2O3 in black NiO material. The transmission electron microscopic (TEM) images engrained the nanospherical shaped green NiO and nanoflower shaped black NiO/Ni2O3 materials. Further, the band gap of black NiO nanoflower was 2.9 eV compared to green NiO having 3.8 eV obtained from UV-vis spectroscopy. Meanwhile, both NiO catalysts were employed for visible light degradation, which yields a 60.3% efficiency of black NiO comparable to a 4.3% efficiency of green NiO within 180 min of exposure. The higher degrading efficiency of black NiO was due to the presence of Ni2O3 and the development of pores, which was evident from the Barrett-Joyner-Halenda (BJH) method. Type IV hysteresis was observed in black NiO nanoflowers with high surface area and pore size measurements. This black NiO/Ni2O3 synthesized from the thermal decomposition method has promoted better photocatalytic degradation of 4-chlorophenol upon exposure to visible light and is applicable for other industrial pollutants.

Narrative of hazardous chemicals in water: Its potential removal approach and health effects.

H2O is essential for life to exist on earth; it is important to guarantee both the quality and supply of water to satisfy world demand. However, it became contaminated by a number of hazardous, inorganic industrial pollutants, which caused a number of issues like irrigation activities and unsafe human ingestion. Long-term exposure to harmful substances can result in respiratory, immunological, and neurological illnesses, cancer, and problems during pregnancy. Therefore, removing hazardous substances from wastewater and natural water sources is crucial. It is necessary to develop an alternate method that can effectively remove these toxins from water bodies, as conventional methods have several drawbacks. This review primarily aims to achieve the following goals: 1) to discuss the distribution of harmful chemicals: 2) to give specifics on numerous possible strategies for getting rid of hazardous chemicals, and 3) its effects on the environment and consequences for human health have been examined.

Recent Advanced Synthesis Strategies for the Nanomaterial-Modified Proton Exchange Membrane in Fuel Cells.

Hydrogen energy is converted to electricity through fuel cells, aided by nanostructured materials. Fuel cell technology is a promising method for utilizing energy sources, ensuring sustainability, and protecting the environment. However, it still faces drawbacks such as high cost, operability, and durability issues. Nanomaterials can address these drawbacks by enhancing catalysts, electrodes, and fuel cell membranes, which play a crucial role in separating hydrogen into protons and electrons. Proton exchange membrane fuel cells (PEMFCs) have gained significant attention in scientific research. The primary objectives are to reduce greenhouse gas emissions, particularly in the automotive industry, and develop cost-effective methods and materials to enhance PEMFC efficiency. We provide a typical yet inclusive review of various types of proton-conducting membranes. In this review article, special focus is given to the distinctive nature of nanomaterial-filled proton-conducting membranes and their essential characteristics, including their structural, dielectric, proton transport, and thermal properties. We provide an overview of the various reported nanomaterials, such as metal oxide, carbon, and polymeric nanomaterials. Additionally, the synthesis methods in situ polymerization, solution casting, electrospinning, and layer-by-layer assembly for proton-conducting membrane preparation were analyzed. In conclusion, the way to implement the desired energy conversion application, such as a fuel cell, using a nanostructured proton-conducting membrane has been demonstrated.

Facile Synthesis of Functionalized Porous Carbon by Direct Pyrolysis of Anacardium occidentale Nut-Skin Waste and Its Utilization towards Supercapacitors.

Preparing electrode materials plays an essential role in the fabrication of high-performance supercapacitors. In general, heteroatom doping in carbon-based electrode materials enhances the electrochemical properties. Herein, nitrogen, oxygen, and sulfur co-doped porous carbon (PC) materials were prepared by direct pyrolysis of Anacardium occidentale (AO) nut-skin waste for high-performance supercapacitor applications. The as-prepared AO-PC material possessed interconnected micropore/mesopore structures and exhibited a high specific surface area of 615 m2 g-1. The Raman spectrum revealed a moderate degree of graphitization of AO-PC materials. These superior properties of the as-prepared AO-PC material help to deliver high specific capacitance. After fabricating the working electrode, the electrochemical performances including cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy measurements were conducted in 1 M H2SO4 aqueous solution using a three-electrode configuration for supercapacitor applications. The AO-PC material delivered a high specific capacitance of 193 F g-1 at a current density of 0.5 A g-1. The AO-PC material demonstrated <97% capacitance retention even after 10,000 cycles of charge-discharge at the current density of 5 A g-1. All the above outcomes confirmed that the as-prepared AO-PC from AO nut-skin waste via simple pyrolysis is an ideal electrode material for fabricating high-performance supercapacitors. Moreover, this work provides a cost-effective and environmentally friendly strategy for adding value to biomass waste by a simple pyrolysis route.

A mechanothermal approach for the synthesis of Fe3O4 nanoparticles as dopant on mesoporous TiO2 for electrochemical determination of catechol.

The subject of water contamination and how it gets defiled to the society and humans is confabulating from the past decades. Phenolic compounds widely exist in the water sources and it is emergent to determine the toxicity in natural and drinking water, because it is hazardous to the humans. Among these compounds, catechol has sought a strong concern because of its rapid occurrence in nature and its potential toxicity to humans. The present work aims to develop an effective electrochemical sensing of catechol using mesoporous structure of Fe3O4-TiO2 decorated on glassy carbon (GC) electrode. The creation of pure TiO2 using the sol-gel technique was the first step in the synthesis protocol for binary nanocomposite, which was then followed by the loading of Fe3O4 nanoparticles on the surface of TiO2 using the thermal decomposition method. The resultant Fe3O4-TiO2 based nanocomposite exhibited mesoporous structure and the cavities were occupied with highly active magnetite nanoparticles (Fe3O4) with high specific surface area (90.63 m2/g). When compared to pure TiO2, catechol showed a more prominent electrochemical response for Fe3O4-TiO2, with a significant increase in anodic peak current at a lower oxidation potential (0.387 V) with a detection limit of 45 µM. Therefore, the prepared magnetite binary nanocomposite can serve as an efficient electroactive material for sensing of catechol, which could also act as a promising electrocatalyst for various electrocatalytic applications.

Mesoporogen free synthesis of CuO/TiO2 heterojunction for ultra-trace detection of catechol in water samples.

Creating mesoporous architecture on the surface of metal oxides without using pore creating agent is significant interest in electrochemical sensors because these materials act as an efficient electron transfer process between the electrode interface and the analytes. Recent advances in mesoporous titanium dioxide (TiO2)-based materials have acquired extraordinary opportunities because of their interconnected porous structure could act as a host for doping with various transition metals or heteroatoms to form a new type of heterojunction. Herein, a simple method is developed to synthesize mesoporous copper oxide (CuO) decorated on TiO2 nanostructures in which homogenous shaped CuO nanocrystals act as dopants decorated on the mesoporous structure of TiO2, resulting in p-n heterojunction nanocomposite. The TiO2 particles exhibit a mesoporous structure with a pore volume of about 0.117 cm3/g is capable to load CuO nanocrystals on the surface. As a result, large pore volume 0.304 cm³/g is obtained for CuO-TiO2 heterojunction nanocomposite with the loading of uniform-shaped CuO nanocrystals on the mesoporous TiO2. The resulting CuO-TiO2 nanocomposite on modified glassy carbon (GC) electrode exhibits good electrochemical performance for oxidation of catechol with the observation of strong enhancement in the anodic peak potential at +0.36 V. The decrease in the overpotential for the oxidation of catechol when compared to TiO2/GC is attributed to the presence of CuO nanocrystals providing a large surface area, resulting in wide linear range 10 nM to 0.57 µM. Moreover, the resultant modified electrode exhibited good sensitivity, selectivity and reproducibility and the sensor could able to determine the presence of catechol in real samples such as lake and river water. Therefore, the obtained CuO-TiO2 nanocomposite on the modified GC delivered good electrochemical sensing performance and which could be able to perform a promising strategy for designing various metal oxide doped nanocomposites for various photochemical and electrocatalytic applications.

Improving the sensitivity for hydrogen peroxide determination with active V2O5 nanocubes incorporated on mesoporous TiO2.

The capacity to generate a constant signal response from an enzyme on an electrode surface has been a fascinating topic of research from the past three decades. To nourish the enzymatic activity during electrochemical reactions, the immobilization of dual enzymes on the electrode surface could prevent the enzymatic loss without denaturation and thus long-term stability can be achieved. For effective immobilization of dual enzymes, mesoporous materials are the ideal choice because of its numerous advantages such as 1. The presence of porous structure facilitates high loading of enzymes 2. The formation of protective environment can withstand the enzymatic activity even at acidic or basic pH values and even at elevated temperatures. Herein, we develop bienzymatic immobilization of horseradish peroxidase (HRP) and cholesterol oxidase (ChOx) on mesoporous V2O5-TiO2 based binary nanocomposite for effective sensing of hydrogen peroxide (H2O2) in presence of redox mediator hydroquinone (HQ). The utilization of redox mediator in second-generation biosensing of H2O2 can eliminate the interference species and reduces the operating potential with higher current density for electrochemical reduction reaction. Using this mediator transfer process approach at HRP/ChOx/V2O5-TiO2 modified GC, the H2O2 can be determined at operating potential (-0.2 V) with good linear range (0.05-3.5 mM) higher sensitivity (1040 µAµM-1 cm-2) and lower detection limit of about 20 µM can be attained, which is due to higher mediation of electrons were transferred to the enzyme cofactors. These interesting characteristics could be due to mesoporous structure of V2O5-TiO2 can induce large immobilization and facilitate higher interaction with enzymes for wide range of biosensing applications.

Electrochemical detection of hydrogen peroxide using micro and nanoporous CeO2 catalysts.

In this research work, focus has been made on a glassy carbon electrode (GCE) modified commercial micro and synthesized nano-CeO2 for the detection of hydrogen peroxide (H2O2). Firstly, CeO2 nanoleaves were prepared by solvothermal route. Both commercially available micro CeO2 and synthesized nano-CeO2 structures were analyzed by different characterization techniques. The Raman spectra of synthesized nano CeO2 has more oxygen vacancies than micro CeO2. SEM images revealed that the synthesized CeO2 acquired leaf-like morphology. The catalyst nano CeO2 offered mesoporosity from nitrogen adsorption-desorption isotherms with massive sites of activation for increasing efficiency. Experiments on determining H2O2 using micro CeO2 or nano-CeO2/GCE was conducted using cyclic voltammetry (CV) and amperometry. Enhanced H2O2 reduction peak current with lower potential was observed in nano-CeO2/GCE. The influence of scan rate and H2O2 concentration on the performance of nano-CeO2/GCE were also studied. The obtained results have indicated that nano-CeO2/GCE showed improved electrochemical sensing behavior towards the reduction of H2O2 than micro-CeO2/GCE and bare GCE. A linear relationship was obtained over 0.001 µM-0.125 µM concentration of H2O2, with good sensitivity 141.96 µA µM-1 and low detection limit of 0.4 nM. Hence, the present nano-CeO2 system will have a great potential with solvothermal synthesis approach in the development of electrochemical sensors.

Tailoring the heterojunction of TiO2 with multivalence CeO2 nanocrystals - for detection of toxic 2-aminophenol.

Enhancing the current signal response for semiconductors is the key factor for designing and fabrication of efficient electrode in electrochemical sensors. By the aid of doping with binary metal oxides, the conductivity of the resultant titanium oxide (TiO2) based nanocomposite will deliver fast electron transfer rate at the heterojunction interface. Herein, by taking advantage of mesoporous structure in TiO2, cubic shaped multivalent cerium oxide (CeO2) was incorporated into the porous cavity by simple ground assisted solvothermal process, which resulted in enormous enhancement in the current response towards detection of 2-aminophenol. The advantage of CeO2 on TiO2 not only involves the loading of binary metal oxide on its mesoporous sites, but also facilitates the formation of CeO2 nanocrystals which induce larger surface area and high electroactive sites with rapid diffusion of target species through pores. As a result, CeO2-TiO2 on modified GC electrode exhibits drastic enhancement in the current response for oxidation of 2-aminophenol with large decrease in the onset potential than TiO2/GC electrode. Furthermore, the CeO2-TiO2 modified electrode shows significant behavior for sensing of 2-aminophenol with wide linear range of 0.01-500 µM. The sensitivity and detection limit were calculated to be 0.603 µA µM cm-2 and 3.5 nM respectively. This work establishes the facile strategy for decoration of binary metal oxide-based nanocomposites as effective electrode and also possible to create new opportunities in the designing and fabrication of variety of efficient electrode in various electrochemical applications.

The role of MOF based nanocomposites in the detection of phenolic compounds for environmental remediation- A review.

Phenolic compounds would be the emerging pollutant by 2050, because of their wide spread applicability in daily life and therefore the adoption of suitable detection methods in which identification and separation of isomers is highly desirable. Owing to the fascinating features, Metal-organic framework (MOF), a class of reticular materials holds a large surface area with tunable shape and adjustable porosity will provide strong interaction with analytes through abundant functional groups resulting in high selectivity towards electrochemical determination of phenolic isomers. Nevertheless, the sensing performance can still be further improved by building MOF network (intrinsic resistance) with functional (conducting) materials, resulting in MOF based nanocomposite. Herein, this review provides the summary of MOF based nanocomposites for electrochemical sensing of phenolic compounds developed from 2015. In this review, we discussed the demerits of pristine MOF as electrode materials, and the requirement of new class of MOF with functional materials such as nanomaterials, carbon nanotubes, graphene and MXene. The history and evolution of MOF nanocomposite-based materials are discussed and also featured the impressive physical and chemical properties. Besides this review discusses the factors influencing the conducting pathway and mass transport of MOF based nanocomposite for enhanced sensing performance of phenolic compounds with suitable mechanistic illustrations. Finally, the major challenges governing the determination of phenolic compounds and the future advancements required for the development of MOF based electrodes for various applications are highlighted.

Switching the solubility of electroactive ionic liquids for designing high energy supercapacitor and low potential biosensor.

Ionic liquids are regarded as one of the most prodigious materials for sustainable technological developments with superior performance and versatility. Hence, in this study, we have reported the design and synthesis of electroactive disubstituted ferrocenyl ionic liquids (Fc-ILs) with two different counter anions and demonstrated the significance of their anion tuneable physicochemical characteristics towards multifunctional electrochemical applications. The Fc-IL synthesized with chloride counter anion (Fc-Cl-IL) displays water-solubility and can be used as a redox additive in the fabrication of supercapacitor. Supercapacitor device with Fc-Cl-IL based redox electrolyte exhibits outstanding energy and power densities of 91 Wh kg-1 and 20.3 kW kg-1, respectively. Meanwhile, ferrocenyl IL synthesized with perchlorate anion (Fc-ClO4-IL) exhibits water-insolubility and can serve as a redox mediator towards construction of a glucose biosensor. The biosensor comprising Fc-ClO4-IL is able to detect glucose at an exceptionally lower potential of 0.2 V, with remarkable sensitivity and selectivity. This study implies that the introduction of electroactive ILs could afford supercapacitor devices with high energy and power densities and biosensors with less detection potential.

Water insoluble, self-binding viologen functionalized ionic liquid for simultaneous electrochemical detection of nitrophenol isomers.

Herein, a water insoluble viologen functionalized ionic liquid (Vio-IL) was designed for the simultaneous electrochemical detection of 2-nitrophenol and 4-nitrophenol. Carboxyl functionalized benzimidazolium based ILs were hierarchically synthesized and the water insoluble carboxylic IL was covalently attached with aminopropylmethyl viologen through DCC coupling to obtain water insoluble Vio-IL gel. Vio-IL was immobilized by simple dropcasting over a multiwalled carbon nanotube deposited screen printed carbon electrode to obtain Vio-IL/MWCNT/SPE. The Vio-IL/MWCNT/SPE exhibited two sets of well-resolved redox peaks corresponding to V2+ to V+• and V+• to V0 redox couple. Furthermore, Vio-IL/MWCNT/SPE has shown excellent electrocatalytic activity towards the reduction of 2- and 4-nitrophenol individually, and also for the simultaneous determination of 2- and 4-nitrophenol. The linear range, sensitivity and detection limit for simultaneous detection of 2-nitrophenol at Vio-IL/MWCNT/SPE were found to be 4-494 µM, 0.884 µA µM-1 cm-2, 1.5 µM and that for 4-nitrophenol were 2-259 µM, 2.615 µA µM-1 cm-2, 0.70 µM. The Vio-IL/MWCNT/SPE established excellent sensitivity and selectivity towards the simultaneous determination of 2- and 4-nitrophenol together with impressive stability and reproducibility. The exemplary analytical parameters achieved are due to the rational immobilization of the mediator covalently in the highly conducting IL/MWCNT backbone which maintained the mediator characteristics effectively.

Hierarchical Core-Shell Structure of 2D VS2@VC@N-Doped Carbon Sheets Decorated by Ultrafine Pd Nanoparticles: Assembled in a 3D Rosette-like Array on Carbon Fiber Microelectrode for Electrochemical Sensing.

The development of two-dimensional (2D) nanohybrid materials with heterogeneous components in nanoscale and three-dimensional (3D) well-ordered assembly in microscale has been regarded as an effective way to improve their overall performances by the synergistic coupling of the optimized structure and composition. In this work, we reported the design and synthesis of a new type of hierarchically core-shell structure of 2D VS2@VC@N-doped carbon (NC) sheets decorated by ultrafine Pd nanoparticles (PdNPs), which were vertically grown on carbon fiber (CF) and assembled into a unique 3D rosette-like array. The resultant VS2@VC@NC-PdNPs modified CF microelectrode integrated the structural and electrochemical properties of the heterogeneous hybridization of core-shell VS2@VC@NC-PdNPs sheets with a unique rosette-like array structure, and gave rise to a significant improvement in terms of electron transfer ability, electrocatalytic activity, stability, and biocompatibility. Under the optimized conditions, the VS2@VC@NC-PdNPs modified CF microelectrode demonstrated excellent electrochemical sensing performance towards biomarker hydrogen peroxide (H2O2) including a high sensitivity of 152.7 µA cm-2 mM-1, a low detection limit of 50 nM (a signal-to-noise ratio of 3:1), as well as good reproducibility and anti-interference ability, which could be used for the real-time in situ electrochemical detection of H2O2 in live cancer cells and cancer tissue. The remarkable performances of the proposed nanohybrid microelectrode will have a profound impact on the design of diverse 2D layered materials as a promising candidate for electrochemical biosensing applications.

In situ growth of Fe(ii)-MOF-74 nanoarrays on nickel foam as an efficient electrocatalytic electrode for water oxidation: a mechanistic study on valence engineering.

In this work, our theoretical results first demonstrate that varying the metal valence in MOFs plays a significant role in tuning their stable intrinsic electronic structure. Different valence Fe(ii) and Fe(iii) based pristine MOF-74 nanoarrays on nickel foam are further synthesized as electrodes for highly efficient electrocatalytic water oxidation.

Heterostructures of mesoporous TiO2 and SnO2 nanocatalyst for improved electrochemical oxidation ability of vitamin B6 in pharmaceutical tablets.

The detection of water soluble vitamins using electrochemical method is widely established in pharmaceutical quality control laboratories, and especially the recent advances in hybrid heterostrucure nanomaterials has devoted to enhance the significant analytical parameters like sensitivity, selectivity and fast response time. Herein, we report the synthesis of a hybrid heterostructure comprising SnO2 nanoparticles supported mesoporous TiO2, and the obtained nanocomposite were fabricated over glassy carbon electrode (GCE) for the electrochemical oxidation of vitamin B6 in pharmaceutical tablets. The designed SnO2-TiO2/GC modified electrode exhibits well-defined oxidation peak with lowering over-potential and larger signal response compared to the pristine counterparts, and it is mainly due to the formation of abundant active surface layer offered by SnO2 cocatalyst, and thus significantly enhances the electrochemical surface area. Differential pulse voltammetry (DPV) measurements revealed a sharp increase in the anodic peak current upon addition of increasing concentration of vitamin B6. The analytical performance of the modified electrode displayed a wide linear range (0.1-31.4 µM), high selectivity, and excellent sensitivity (759.73 µA mM-1 cm-2) with low detection limit (35 nM). Thus, the resultant mesoporous hybrid nanocatalyst provides an efficient electrochemical platform for determination of various potential analytes.

One-step solution synthesis of a two-dimensional semiconducting covalent organometallic nanosheet via the condensation of boronic acid.

In this work, a 2D covalent organometallic nanosheet (COMS) was designed and successfully synthesized through the one-step conjunction of a terpyridine-metal-terpyridine (TMT) sandwich coordinate motif with borate ester covalent heterocyclic (B3O3) linkage via the condensation of boronic acid. The obtained 2D COMS with a cobalt coordination center (2D COMS-Co) showed promising p-type semiconducting properties.

Aldehyde functionalized ionic liquid on electrochemically reduced graphene oxide as a versatile platform for covalent immobilization of biomolecules and biosensing.

An aldehyde functionalized ionic liquid, (3-(3-formyl-4-hydroxybenzyl)-3-methylimidazolium hexafluorophosphate) (CHO-IL) has been employed herein as a multiple host platform for the covalent immobilization of mediator as well as enzyme. The CHO-IL was immobilized on electrochemically reduced graphene oxide (ERGO) through the π-π stacking of hydroxybenzyl and imidazolium groups with ERGO and subjected to further covalent attachment of Azure A (Azu-A) mediator or glucose oxidase (GOx) enzyme. Electroactive, water soluble organic dye Azu-A was effectively immobilized to the host IL through simple Schiff base reaction. Azu-A was rendered leak-free in the electrode setup and also responded well for the amperometric determination of H2O2 over a linear range of 0.03-1mM with a detection limit and sensitivity of 11.5µM and 133.2µAmM-1cm-2, respectively. Further, attempts were made to explore the CHO-IL platform for the covalent immobilization of GOx enzyme which served well in retaining the enzyme nativity, reactivity and stability. Under optimized conditions, mediatorless GOx biosensor developed based on direct electrochemistry has exhibited an impressive analytical signal towards glucose detection in the linear range of 0.05-2.4mM with a detection limit and sensitivity of 17µM and 17.7µAmM-1cm-2, respectively. The reliability of the proposed Azu-A based chemical sensor and GOx based biosensor towards the determination of H2O2 and glucose in the real samples have been demonstrated. The remarkable analytical parameters and long term stability of both the sensors could be envisioned as a result of facile immobilization platform and immobilization strategy.

A bioinspired ionic liquid tagged cobalt-salophen complex for nonenzymatic detection of glucose.

The development of efficient and cost effective nonenzymatic biosensors with remarkable sensitivity, selectivity and stability for the detection of biomolecules, especially glucose is one of the major challenges in materials- and electrochemistry. Herein, we report the design and preparation of nonenzymatic biosensor based on an ionic liquid tagged cobalt-salophen metal complex (Co-salophen-IL) immobilized on electrochemically reduced graphene oxide (ERGO) for the detection of glucose via an electrochemical oxidation. The bioinspired Co-salophen-IL complex has been synthesized and immobilized on ERGO, which was previously deposited on a screen printed carbon electrode (SPE) to form the Co-salophen-IL/ERGO/SPE nonenzymatic biosensor. The electrochemical behaviour of this modified electrode was studied using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Notably, the Co-salophen-IL/ERGO/SPE biosensor exhibited excellent electrocatalytic activity towards glucose oxidation in 0.1M NaOH, based on which an amperometric sensor has been developed. The modified electrode has shown prominent performance towards glucose detection over a wide linear range from 0.2µM to 1.8mM with a detection limit and sensitivity of 0.79µM and 62µAmM-1 respectively. The detection was carried out at 0.40V and such a less working potential excludes the interference from the coexisting oxidizable analytes. The role of Co-salophen, IL and ERGO in the electrocatalytic activity has been systematically investigated. Furthermore, the biosensor demonstrated high stability with good reproducibility.