Electro Activity Research Articles

Lead‐Free Perovskite‐Based Photocatalysts for Solar‐Driven Chemistry Technologies

AbstractThe high consumption of fossil fuels and concomitant contamination of the environment have promoted the search for new, low‐cost, and cleaner energy sources to satisfy the current energy demand around the world, decreasing the levels of greenhouse gas emissions to the atmosphere. One of the promising strategies to facilitate the generation of renewable energy involves solar‐driven chemical reactions, by using photocatalysts with improved sunlight absorption and carrier transfer abilities. Lead‐free halide perovskites (LFHPs) are good candidates, showing mesmerizing optical features, modulable band structure, oxidizing/reducing capability, and less toxicity compared to their Pb‐analogous. However, the literature reporting the photo(electro)chemical (PEC) properties of the LFHPs‐based materials for solar energy production is scarce. This review describes the current state‐of‐the‐art exhibiting the influence of the dimensionality, chemical composition and the formation of heterojunctions based on LFHPs on their photo(electro)activity for conducting solar‐driven hydrogen evolution, carbon dioxide (CO2) reduction, and the degradation of recalcitrant pollutants to obtain added‐value chemicals. In this way, it is also included the main challenges to be faced. Furthermore, we address some potential LFHPs to be explored in PEC systems, opening up the gamut of possibilities to consolidate the solar‐to‐chemical transformation as an innovative alternative to favor environmentally friendly energy production.

Sensitive detection of miR-9 in human serum: An electrochemical approach utilizing robust gold nanostructures for early diagnosis of lung cancer

The complexity of procedures, concentration dependency, and time consumption associated with traditional microRNA analysis platforms render them unsuitable for point-of-care (POC) diagnostics. In order to address the challenges posed by reduced electro activity resulting from the use of surfactants or stabilizers in the fabrication of nanostructures for biosensors, we have developed a customized method for gold nanofabrication. This technique involves the deposition of gold nanostructures (Au-NS) onto FTO electrodes without the use of surfactants or stabilizers, followed by the immobilization of thiolated ssDNA onto the substrate surface. To assess the performance of the resulting biosensor, we hybridized miR-9 with the ssDNA and determined the linear detection range to be from 10 zM to 100 nM. Our approach provides a unique solution to the limitations associated with electrochemical and/or SERS biosensors and demonstrates the potential for improved biosensing applications. The acquired data demonstrate the superior ability of nanostructured biosensors for label-free detection of miR-9 at attomolar limit of detection (LOD = 0.012 aM). The HRSEM data also revealed a unique nanostructure; the AFM topology confirmed an increase in the surface area aspect ratio features; and the GIXRD analysis approved the fabricated AuNSs on FTO electrodes. Furthermore, electrochemical analysis of AuNS’ platforms showed considerable electroactivity compared to bare FTO. In addition to its previously demonstrated performance, our biosensor exhibited outstanding selectivity in the detection of miR-486. The use of AuNSs in our biosensor fabrication results in excellent selectivity, high electroactivity, and ease of fabrication, rendering it an ideal option for both biosensing and cancer screening applications.

Synthesis, spectral, in vitro microbial and DNA cleavage studies of isatin bishydrozone metal complexes

ONNO donor Schiff bases with recent group of Co(II), Ni(II), and Cu(II) complexes have been created and analyzed using spectroscopic research, thermal analysis, magnetic susceptibility, conductance tests, and elemental analysis. Via lactonyl oxygen and azomethine nitrogen, the Schiff bases are coordinated to the metal ion. In most common organic solvents, the complexes are insoluble but soluble in DMSO. The Co(II), Ni(II), and Cu(II) complexes' antibacterial properties, tested on quartet bacteria and two fungi strains showed an increased activity with respect to the Schiff bases. The Co(II), Ni(II) and Cu(II) complexes show more pronounced DNA cleaving activity. On cyclic voltammograms, the Cu(II) or Co(II) complexes tested in the DMSO solution showed metal-centered electro activity between 1.5 and +1.5 V.

Behavior of Al Impurity in ZnO Films: Influence of Al‐Level Doping on Structure, X‐Ray Photoelectron Spectroscopy and Transport Properties

Transparent and conductive ZnO:Al thin films have been deposited by a reactive magnetron sputtering using the layer‐by‐layer growth method. The grown Al‐doped ZnO films of about 100 nm thickness on Si and glass substrates have been investigated with respect to the crystalline phase by X‐ray diffraction (XRD), surface morphology by atomic force microscopy (AFM), chemical bonding, and the electronic structure by measuring the X‐ray photoelectron spectroscopy (XPS) core‐level and valence‐band spectra of the ZnO:Al films. The influence of Al content in ZnO films on structure, optical, and XPS spectra, transport parameters n, μ, ρ have been studied. The weak temperature dependence of conductivity in the temperature range 77–300 K suggests that Al3+ is a fully ionized impurity that provides the values of electron concentration in the range 7 × 1019–2.44 × 1020 cm−3. Al electroactivity (EA) in ZnO films is diminishing with Al content increases. A strong decrease in Al EA from 60% to 30% is observed for ZnO:Al films within 0.93–1.22 at% of Al that indicates on the enhancement of concentration of acceptor native and/or neutral complex defects in ZnO.

Green synthesis of graphene-based metal nanocomposite for electro and photocatalytic activity; recent advancement and future prospective

The presence of pollutants in waste water is a demanding problem for human health. Investigations have been allocated to study the adsorptive behavior of graphene-based materials to remove pollutants from wastewater. Graphene (GO) due to its hydrophilicity, high surface area, and oxygenated functional groups, is an effective adsorbent for the removal of dyes and heavy metals from water. The disclosure of green synthesis opened the gateway for the economic productive methods. This article reveals the fabrication of graphene-based composite from aloe vera extract using a green method. The proposed mechanism of GO reduction via plant extract has also been mentioned in this work. The mechanism associated with the removal of dyes and heavy metals by graphene-based adsorbents and absorptive capacities of heavy metals has been discussed in detail. The toxicity of heavy metals has also been mentioned here. The Polyaromatic resonating system of GO develops significant π-π interactions with dyes whose base form comprises principally oxygenated functional groups. This review article illustrates a literature survey by classifying graphene-based composite with a global market value from 2010 to 2025 and also depicts a comparative study between green and chemical reduction methods. It presents state of art for the fabrication of GO with novel adsorbents such as metal, polymer, metal oxide and elastomers-based nanocomposites for the removal of pollutants. The current progress in the applications of graphene-based composites in antimicrobial, anticancer, drug delivery, and removal of dyes with photocatalytic efficacy of 73% is explored in this work. It gives a coherent overview of the green synthesis of graphene-based composite, various prospective for the fabrication of graphene, and their biotoxicity.

A comprehensive review of hydrogen generation by water splitting using 2D nanomaterials: Photo vs electro-catalysis

Transition metal carbides/nitrides (MXenes) with eccentric properties are emerging 2D nanomaterials with intriguing applications in the photo and electro-catalytic water splitting (Wsp). MXenes have a regular planer structure with a large specific surface area (SSA), excellent hydrophilicity, metallic conductivity, and a wide range of functionalities and surface termination groups, making them a promising candidate for long-term hydrogen generation (H2, gen). As a result, their use as electro and photo-catalysts in Wsp to solve energy and environmental challenges has increased. MXenes were proposed to overcome major drawbacks of TiO2, the most commonly used photo-catalyst in solar-driven Wsp, such as high band gap and fast recombination of photo-induced charge carriers. MXene has been rigorously investigated based on TiO2 modification (i.e. in-situ derived MXene-TiO2 and MXene/TiO2 nanocomposite) as well as Metal-MXene co-catalyst that provides simple electron channelization to improve overall electro and photo-catalytic activity (CatA)toward Wsp and increase the hydrogen evolution reaction (HER). However, several issues must be resolved before practical applications may be considered, such as weak environmental capabilities and limited intrinsic catalytic activities. Although there have been a few review papers on the synthesis, properties, and applications of Mxenes in various fields, this present work focuses on the most current advances in the synthetic of MXene-derived TiO2 and MXene/TiO2 nanohybrid composites as well as Metals-MXene nanocomposite, clarifying the charge carrier separation mechanism in connection to the formed Schottky junction at MXene- elements interface to attaining high photo-catalytic H2, gen. Furthermore, technical challenges, and enhanced catalytic performance as well as materials design and MXenes derivative with structural features and activity were presented. MXenes' catalytic mechanism is carefully outlined, along with its photocatalytic and electrocatalytic Wsp properties. According to the literature review, Ti3C2 can be combined with a variety of materials to produce electro or photo-catalysis with distinct layered morphology (0D, 1D, 2D, 3D), abundant surface termination groups, and enhanced photo-electrical activities. MXene-derived TiO2 and MXene/TiO2 nanohybrid composites have been proposed as viable electro and photo-catalytic H2, gen alternatives. The photo-catalytic H2, gen rate from Wsp over MXene-derived TiO2 can range from 20 to 50, 000 mol.g-1h−1, with Co-Chl@Ti3C2Tx producing the most.

Interference-less vitamin C biosensor based on electrochemically prepared and encapsulated poly (aniline) into silicate network in mild acidic condition

Extending electroactivity of the silica-poly(aniline) (Silica-PANI), prepared by electro-polymerization of N-[3-(trimethoxysilyl)propyl] aniline (TMSPA) monomer, to the highly basic pH is presented. The electrochemical reversibility of the Silica-PANI and the regeneration of its electroactivity are confirmed by the results of cyclic voltammetry (CV). The electro activity of the Silica-PANI electrode extended to highly basic condition, even at pH 13 and it was confirmed using UV–visible spectroscopy. In addition, the regeneration of electroactivity of Silica-PANI electrode was verified in HCl solution, before and after cycling the electrode in KOH solution for 50 cycles. The electrode retains its electrochemical reversibility, demonstrating that Silica-PANI electrode is not influenced by KOH solution and chemically stable. Electrocatalytic activity of Silica-PANI electrode was investigated and it displays catalytic activity towards oxidation of Vitamin C (ascorbic acid, AA). Using the Silica-PANI electrode, the amperometric measurements were performed at an applied potential of 0.07 V and a linear response of Vitamin C was obtained in the range from 10 μM to 60 μM and sensitivity of 5 nA/μM. Interference studies for Vitamin C at Silica-PANI electrode were also examined using electroactive biomolecules such as dihydronicotinamide adenine dinucleotide (NADH), dopamine (DA), uric acid (UA) and H2O2, respectively. It uncovered that almost diminished response of its interference for Vitamin C at Silica-PANI electrode.

Electrocatalytic study of carbon dots/ Nickel iron layered double hydroxide composite for oxygen evolution reaction in alkaline medium

The synthesis and strategic deployment of inexpensive, efficient, and robust catalysts for the oxygen evolution reactions (OER) has assumed importance due to their key role in energy conversion and storage. In this work, Cyamopsis tetragonoloba extract derived nitrogen doped carbon dots (NDCDs) supported NiFe layered double hydroxide stacked sheets (NiFe LDH@NDCDs) had been successfully synthesized by easy solvothermal method. Structural morphology and crystalline nature of the synthesized NiFe LDH@NDCDs were characterized by Scanning electron microscopy (SEM), High resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction spectroscopy. The performance of the synthesized NiFe LDH@NDCDs in electrocatalytic oxygen evolution reaction (OER) was estimated by linear sweep voltammetry (LSV), Tafel, Electrochemical Impedance spectroscopy (EIS), cyclic voltammetry, and chronopotentiometry measurements in 0.1 M KOH. The synthesized NiFe LDH@NDCDs demonstrated the small overpotential of 0.385 VRHE to attain current density of 10 mA/cm2, which was lesser than NiFe LDH (0.425 VRHE), the state of the art (RuO2 = 0.422 VRHE), NDCDs (0.534 VRHE) and Bare Ni foam (0.541 VRHE). The calculated Tafel slopes of synthesized NiFe LDH@NDCDs showed smaller value (93 mV/dec) than NiFe LDH, RuO2, and Bare Ni foam. The EIS studies exposed that the total resistance (R1 + R2) of NiFe LDH@NDCDs (63.85 Ω/cm2) was lower than the total resistance of NiFe LDH (82.58 Ω/cm2) and resistance of Bare Ni foam (123.8 Ω/cm2), which revealed the good conductivity and electro activity of NiFe LDH@NDCDs. Moreover, the stability of the synthesized NiFe LDH@NDCDs was analyzed by chronopotentiometry for 6 h at a constant current density of 10 mA/cm2. Thus the results of the present study established NiFe LDH@NDCDs as an efficient electrocatalyst for the OER in alkaline medium.

Effect of pulsed ion-beam treatment on the electronic and optical properties of GaN epitaxial films on sapphire

GaN films epitaxially grown on sapphire substrates and stored for more than a year under normal conditions were treated using pulsed mixed carbon-hydrogen ion beam. The electronic structure transformations of GaN on sapphire samples were studied using X-ray photoelectron spectroscopy (XPS), optical absorption, photoluminescence and density functional theory (DFT)-based simulations after such treatment. Weak acidification in the form of Ga—N…O was revealed by XPS method for both as-grown and ion-irradiated GaN on sapphire samples. GaN decomposition and Ga-loss effects were not detected after pulsed ion-beam treatment (PIBT), either experimentally or theoretically. It was shown that PIBT promotes a narrowing of the bandgap, changes the vacancy concentration in the surface region, and provides hydrogenation of the surface with the formation of hydroxyl groups in nondefective areas of the surface and near surface layers. PIBT-induced densification of the layers is observed due to annealing of vacancies; no detectable changes in the surface area morphology were found. The weak shift of the valence band edge corresponds to the contribution from areas with more nitrogen defects. The presence of these states in the bandgap could be the possible source of an increase in the electro and photocatalytic activity of GaN epitaxial films.

Electrochemical Behavior of Chloroquin, Azithromycin and Hydroxychloroquin onto Carbon-Clay Paste Electrode Doped with Titanium Oxide (TiO<sub>2</sub>)

The aim of this work is to prepare and characterize a carbon-clay paste electrode doped with Titanium Oxide (CPEA/TiO₂). This electrode is used to study the electrochemical behavior of drugs such as Chloroquin, Azithromycin and Hydroxychloroquin. The morphological, structural and functional characteristics of this electrode were carried out using X-ray diffraction (XRD), selected area electron diffraction (SAED), scanning electron microscopy (SEM), Fourrier transform infrared spectroscopy (FTIR). The electrochemical characterization was made by Cyclic Voltammetry (CV) in the potential range [-0.1V; 0.9V], in a phosphate buffer solution (0.1M; pH = 6.4); focused on the detection of an inorganic complex (ion [Fe(CN)₆]^3- (1mM)). The application was made focused on the detection of organic macromolecules such as azithromycin (AZI), chloroquin (CHL) and hydroxychloroquin (HYC). CPEA/TiO₂ was then subjected to electroanalysis in the same concentrations of the combinations AZI+CHL and AZI+HYC. However, in the presence of analyte the phenomena are irreversible with a dominance of oxidation phenomena. The electroactivity of the drugs used initially concerns the hydroxyl groups, observed around 0.050V (oxidation potential of the hydroxyl function in an intermediate form) and 0.560V (oxidation potential of the intermediate and in the carbonyl group). Secondly, the electro activity of the tertiary amine is highlighted by the potential value of 0.690V (attributable to the oxidation of the tertiary amine into an ammonium hydroxyl derivative). Current densities are more pronounced, which suggests a new molecule with significant electro activity. The oxidation mechanism is proposed. The electroactivity of the excipients (Lactose and Starch) used in these drugs is not negligible and evolves when going from one drug to two. However, the excipients are less noticeable in the AZI+HYC combination than in AZI+CHL.

Performance of Polydopamine Complex and Mechanisms in Wound Healing.

Polydopamine (PDA) has been gradually applied in wound healing of various types in the last three years. Due to its rich phenol groups and unique structure, it can be combined with a variety of materials to form wound dressings that can be used for chronic infection, tissue repair in vivo and serious wound healing. PDA complex has excellent mechanical properties and self-healing properties, and it is a stable material that can be used for a long period of time. Unlike other dressings, PDA complexes can achieve both photothermal therapy and electro activity. In this paper, wound healing is divided into four stages: antibacterial, anti-inflammatory, cell adhesion and proliferation, and re-epithelialization. Photothermal therapy can improve the bacteriostatic rate and remove reactive oxygen species to inhibit inflammation. Electrical signals can stimulate cell proliferation and directional migration. With low reactive oxygen species (ROS) levels, inflammatory factors are down-regulated and growth factors are up-regulated, forming regular collagen fibers and accelerating wound healing. Finally, five potential development directions are proposed, including increasing drug loading capacity, optimization of drug delivery platforms, improvement of photothermal conversion efficiency, intelligent electroactive materials and combined 3D printing.

Effect of CeO2 Presence on the Electronic Structure and the Activity for Ethanol Oxidation of Carbon Supported Pt

Pt/CeO2/C electrocatalysts in different compositions were prepared and their structural characteristics and activities for ethanol oxidation in alkaline media were evaluated. In the presence of CeO2, an increase in the platinum particle size was observed. XANES measurements indicated that the Pt d-band vacancies increased with increasing CeO2 amounts. For the first time, the decrease in electro activity was described to an electronic effect for high CeO2 contents. The dependence of the activity for ethanol oxidation on CeO2 content went to a maximum, due to the counteracting bifunctional and electronic effects of the metal oxide.

Surface engineering of Ni-P electrode by cobalt oxide co-deposition for electrochemical hydrogen evolution reaction

Catalytic electrode assisted water electrolysis is a potential method of clean hydrogen production. The present work deals with the surface modification of Ni-P electrode (NPE) by electroless co-deposition of cubic phased cobalt oxide, for enhanced hydrogen evolution from 1 M NaOH solution. The excellent coating thickness (9–10 µm), hardness (547 HVN) and wear resistant properties of 5 g/L Co3O4 deposited Ni-P divulge its appropriateness for industrial use. The co-operative interaction of cubic phased Co3O4 with Ni and P improves the interfacial charge transfer reaction (lower Rct of 66 Ω) and cause HER at a reduced overpotential (71 mV at 10 mA/cm2). The mild steel supported NPE/Co3O4 coating is highly porous and conductive. And the evolution of hydrogen from 1 M NaOH solution is kinetically controlled by Volmer process. The mechanism of entire catalyst assisted water splitting follows Volmer-Tafel route. The activity of the electrode was thoroughly evaluated. Furthermore the continuous evolution of hydrogen for a period of 50 h by the metal oxide modified NPE, reiterate the sustainability of electro activity. The implemented surface engineering strategy for Ni-P electrode by the spinel structured cubic phased Co3O4 co-deposition to get a rough and porous surface morphology is by a relatively less expensive electroless deposition method. The excellent value for electro catalytically active surface area (ECSA = 93.14 cm2) and long term activity in alkaline solution made NPE/5 g/L Co3O4, a competent catalytic electrode for HER.

NanoZnO Modified Polymer Electret Electrodes for Cyclic Voltammetry of Some Synthasized Anils

Preparation and characterization of pure and nano-ZnO doped PVDF-PMMA polymer blend-nanocomposites for investigating the charge storage and transfer effects have been studied. Fourier transform infrared (FTIR) was used for characterization and structure elucidation of the blended polymers. Polymer microstructure, chain conformation and polymer morphology were studied to establish the structure activity relations. Cyclic voltammetry (CV) was chosen to study the electronic properties of the modified polymers as it furnishes information as a function of an energy scan. The effectiveness of CV results from its capability of rapidly observing the redox behavior of the analyte over a wide potential range. Electrode reactions of the intermediates and the products formed during the forward scan have been studied for sulphonamide analogues of synthesized azomethines. Comparative electro activity of plain glassy carbon electrode and the PVDF-PMMA polymer blend-nanocomposite electrets modified electrode was studied.

Electrochemical determination of malondialdehyde biomarker in exhaled breath condensate using poly arginine functionalized by graphene quantum dots and chitosan

Background: Lipid peroxidation is a prominent manifestation of free radical activity in biological systems, and it is involved in the development of different diseases such as cancer or cardiovascular and liver diseases. Malondialdehyde (MDA) is globally recognized as a scientifically accepted biomarker of oxidative stress. Due to the significance of MDA as a marker of lipid peroxidation and because of its elevations in various diseases, the assessment of MDA with new and reliable assays, the development of a fast, sensitive, and selective method to detect MDA with simple instruments is necessary. Methods: This study used the electro polymerization of a low toxic and biocompatible polymer with entitle poly arginine-graphene quantum dots-chitosan (PARG-GQDs-CS) as a novel strategy for surface modification of glassy carbon (GC) surface and preparation a new interface for measurement of MDA in human exhaled breath condensate (EBC). Nanocomposite PARG/CS/GQDs the method of precipitation out of place (ex situ) on the electrode surface was prepared. To verify sequestration nanobiopolymer synthesized Scanning electron microscope images (SEM) were recorded. To identify and study the behavior of malondialdehyde electrochemical methods such as cyclic voltammetry and differential pulse voltammetry were used. Results: The scanning electron microscopy (SEM) images indicated immobilization of uniformly CS and GQDs onto PARG film. The modified electrode appeared as an effective electro activity for detection of MDA. Under the optimized analysis conditions and physiological pH, the prepared sensor showed one oxidation processes for MDA at potentials about 1 V vs. Ag/AgCl with a low limit of quantification (LLOQ) 5.94 nM. Conclusion: The Glassy carbon electrod modified by poly-arginine/chitosan/graphene quantum dots, has good electrical activity for Electro-oxidation malondialdehyde that could be due to synergistic effect poly-arginine, graphene quantum dots and chitosan to create many active sites for this purpose.

Scanning Electrochemical Cell Microscopy (SECCM) Chronopotentiometry: Development and Applications in Electroanalysis and Electrocatalysis

Scanning electrochemical cell microscopy (SECCM) has been applied for nanoscale (electro)activity mapping in a range of electrochemical systems but so far has almost exclusively been performed in controlled-potential (amperometric/voltammetric) modes. Herein, we consider the use of SECCM operated in a controlled-current (galvanostatic or chronopotentiometric) mode, to synchronously obtain spatially resolved electrode potential (i.e., electrochemical activity) and topographical "maps". This technique is first applied, as proof of concept, to study the electrochemically reversible [Ru(NH3)6]3+/2+ electron transfer process at a glassy carbon electrode surface, where the experimental data are in good agreement with well-established chronopotentiometric theory under quasi-radial diffusion conditions. The [Ru(NH3)6]3+/2+ process has also been imaged at "aged" highly ordered pyrolytic graphite (HOPG), where apparently enhanced electrochemical activity is measured at the edge plane relative to the basal plane surface, consistent with potentiostatic measurements. Finally, chronopotentiometric SECCM has been employed to benchmark a promising electrocatalytic system, the hydrogen evolution reaction (HER) at molybdenum disulfide (MoS2), where higher electrocatalytic activity (i.e., lower overpotential at a current density of 2 mA cm-2) is observed at the edge plane compared to the basal plane surface. These results are in excellent agreement with previous controlled-potential SECCM studies, confirming the viability of the technique and thereby opening up new possibilities for the use of chronopotentiometric methods for quantitative electroanalysis at the nanoscale, with promising applications in energy storage (battery) studies, electrocatalyst benchmarking, and corrosion research.

Modified Screen-Printed and Carbon Paste as Ion-Selective Electrodes for the Determination of Ramipril Drug in Pharmaceutical and Biological Samples

Ramipril was a prodrug and it was an angiotensin converting enzyme (ACE) inhibitor which can be used to treat congestive heart failure and hypertension. In this study, the electro activity and the performance characteristics of modified screen-printed (MSPEs) and carbon paste (MCPEs) electrodes with different types of ion pairs had been studied in order to determine ramipril (RAM) drug in pure solution, pharmaceutical formulations and biological fluid samples. The ion pair formation between RAM and phosphomolybdic acid (PMA) or phosphotungstic acid (PTA) or sodium teteraphenyl borate (Na-TPB) was the basis of preparation of modified ion selective electrodes used in this study. The surface analysis of the electrodes was studied using scanning electron microscope (SEM) and X-ray diffraction (XRD). The electrodes showed linear response with good Nernstian slope of 58.50±1.08, 59.00±0.96, 59.60±0.73 mV decade-1 for MSPEs modified with RAM-TPB, RAM-PMA and RAM-PTA ion pairs, respectively, and 59.20±0.96, 58.90±1.01 mV decade-1 for MCPEs modified with RAM-TPB and RAM-PTA ion pairs, respectively, over the concentration range from 5.0 x 10-7 to 1.0 x 10-2 mol L-1. Although, the two types of electrodes provided response time of about 4 s for MSPEs and 5 s for MCPEs and exhibited lifetimes of 99 to 92 days for MSPE electrodes and 67 days for both electrodes of MCPEs on pH range from 2 to 5 for MSPEs and 2 to 4 for MCPEs. They showed high thermal stability according to the isothermal coefficients values. Selectivity coefficients of RAM sensors relative to a number of potential interfering materials were investigated. The developed method was found to be simple, precise and accurate when compared with the reported method.

Preparation of Co-MOF derived Co(OH)2/multiwalled carbon nanotubes as an efficient bifunctional electro catalyst for hydrazine and hydrogen peroxide detections

Abstract Metal–organic frameworks (MOFs) are the more desirable electrode materials in the recent development of electrocatalyts. Still, the electrocatalytic behavior as well as the stability of the prepared MOFs were diminished by its poor conductance. In this work, Cobalt hydroxide (Co (OH)2) functionalized multi-walled carbon nanotubes (MWCNTs) with enhanced electro activity has been prepared using Co-based metal−organic framework (Co MOF, ZIF-67) templates through room temperature electrochemical synthesis. The as synthesized composite has been utilized in the construction of MWCNTs-Co(OH)2 modified glassy carbon electrode (GCE) for the determination of hydrazine (N2H4) and hydrogen peroxide (H2O2). The higher electrochemical performance of MWCNTs-Co(OH)2/GCE compared to individual MWCNTs/GCE and Co(OH)2/GCE was evident from the cyclic voltammetric studies. The characterizations of the composite have been carried out using various techniques. The electrochemical parameters such as linear range, limits of detection and sensitivity of MWCNTs-Co(OH)2/GCE were found to be more comparable with the previous N2H4 and H2O2 amperometric sensors reported in the literatures. The outcomes of practicability inspections were adequate with the recovery results of conventional methods. The high selectivity of MWCNTs-Co(OH)2 modified GCE towards N2H4 and H2O2 has been further demonstrated in the presence of several biologically interfering molecules.

Silver nanoparticles decorated polyaniline nanocomposite based electrochemical sensor for the determination of anticancer drug 5-fluorouracil

A highly efficient electrochemical sensor for the analysis of anticancer drug 5-fluorouracil (5-FU), is fabricated based on silver nanoparticles-polyaniline nanotube (AgNPs@PANINTs). AgNPs@PANINTs nanocomposite has been synthesized by a simple one-step method. Synthesized AgNPs@PANINTs nanocomposite was studied by Fourier transform infrared spectrometry, Scanning Electron Microscopy and Energy Dispersive X-ray. The fabricated PANINTs@AgNPs PGE was applied to the electrochemical sensing of 5-FU. Cyclic voltammetry and differential pulse voltammetry experiments illustrated high electro activity for the AgNPs@PANINTs nanocomposite. The study was explored using the Taguchi experimental design method. Electrochemical measurements using differential pulse voltammetry showed a wide linear relationship between 5-FU concentration and peak height within the range 1.0–300.0 μM with a low detection limit (0.06 μM). Also, the fabricated sensor showed excellent selectivity in the presence of two anticancer drugs and a number of other interfering compounds. The as-prepared sensor showed to be a promising device for a simple, rapid, and direct analysis of 5-FU.

The Effect of Intermittent Limiting Anodic Current Stimulation on the Electro Activity of Anodic Biofilms

Electro active biofilms is key components of bio electrochemical systems. Anodic biofilms formed by a potentialadaptive way (i.e., operation with constant external resistance or poised anode potentials) generally lack the ability to adapt to limiting currents. In the present study, a strategy based on intermittent limiting anodic current application was first employed to directly stimulate the current-adaptive growth of anodic biofilms, aiming to obtain electro active biofilms with high current adaptation. Series of intermittent limiting anodic current stimulations exhibit effectiveness for enhancing the electro-activity of anodic biofilms. Porous thick anodic biofilms with less extracellular polymeric substance production could be obtained by series of intermittent limiting anodic currents application from thin biofilms, generating robust anodic biofilms. The high stable power output of 4.35 W m-2 could be achieved with robust anodic biofilms at high working current of 9.5 A m-2. The present study show that current is a crucial factor influencing the performance of electro-active biofilms, suggesting that an alternative current-adaptive method could be developed for the growth of electro active biofilms with high performance.