Single-laser fabrication of nitrogen-doped porous graphene from chitosan/polyimide for the electrochemical determination of dextromethorphan

A simple and effective disposable electrode was developed for the electrochemical detection of dextromethorphan (DEX) in pharmaceutical and forensic samples. Polyimide was treated with chitosan before being used to create the electrode through single-laser fabrication of nitrogen-doped porous graphene. The laser power and speed were optimized to achieve optimal performance. Scanning electron microscopy, energy dispersive X-ray, Raman and Fourier transform infrared spectroscopy were used to characterize the morphology of fabricated materials. The electrochemical characterization of electrodes was studied by using cyclic voltammetry and electrochemical impedance spectroscopy. The electrochemical behavior of DEX was investigated using cyclic voltammetry and analytical measurements were performed using differential pulse voltammetry. Differential pulse voltammetry was optimized in terms of buffer type, buffer pH, potential pulse, time pulse, potential step, scan rate, deposition potential, and deposition time. In the optimal condition, two linear ranges were observed, ranging from 2.5 to 25 μmol L-1 and 25 to 400 μmol L-1. The limit of detection (LOD) was 1.8 μmol L-1. The developed method produced a statistically significant agreement with high-performance liquid chromatography for the determination of DEX.

Surface adsorption and corrosion resistance performance of modified chitosan: Gravimetric, electrochemical, and computational studies

Two novel chitosan derivatives (water soluble and acid soluble) modified with thiocarbohydrazide were produced by a quick and easy technique using formaldehyde as links. The novel compounds were synthesized and then characterized by thermogravimetric analysis, elemental analysis, nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, and differential scanning calorimetry. Their surface morphologies were examined using scanning electron microscopy. These chitosan derivatives could produce pH-dependent gels. The behavior of mild steel in 5 % acetic acid, including both inhibitors at various concentrations, was investigated using gravimetric and electrochemical experiments. According to the early findings, both compounds (TCFACN and TCFWCN) functioned as mixed-type metal corrosion inhibitors. Both inhibitors showed their best corrosion inhibition efficiency at 80 mg L-1. TCFACN and TCFWCN, showed approximately 92 % and 94 % corrosion inhibition, respectively, at an optimal concentration of 80 mg L-1, according to electrochemical analysis. In the corrosion test, the water contact angle of the polished MS sample at 87.90 °C was reduced to 51 °C. The water contact angles for MS inhibited by TCFACN and TCFWCN in the same electrolyte were greater, measuring 78.10 °C and 93.10 °C, respectively. The theoretical results also support the experimental findings.

Chitosan lecithin nanocomposite based electrochemical biosensor for glycine detection in biological matrices

Increased glycine concentrations are associated with altered metabolism of cancer cells and is reflected in the bodily fluids of the brain cancer patients. Various studies have been conducted in past to detect glycine as an imaging biomarker via NMR Spectroscopy tools. However, the use is limited because of the low concentration and different in vivo detection due to overlapping of peaks with myo-inositol in same spectral position. Alongside, little is known about the electrochemical potential of Glycine as a biomarker for brain cancer. The prime impetus of this study was to check the feasibility of glycine as non-invasive biomarker for brain cancer. A divergent approach to detect glycine "non-enzymatically" via unique chitosan lecithin nanocomposite has been utilised during this study. The electrochemical inactivity at provided potential that prevented glycine to get oxidized or reduced without mediator was compensated utilising the chitosan-lecithin nanocomposite. Thus, a redox mediator (Prussian blue) was used for high sensitivity and indirect detection of glycine. The chitosan nanoparticles-lecithin nanocomposite is used as a matrix. The electrochemical analysis of the onco-metabolomic biomarker (glycine) utilizing cyclic voltammetry in glycine spiked multi-Purpose artificial urine was performed to check distribution of glycine over physiological range of glycine. A wide linear range of response varying over the physiological range from 7 to 240 μM with a LOD 8.5 μM was obtained, showing potential of detection in biological samples. We have further evaluated our results via simulating the interaction of mediator and matrix with Glycine by HOMO-LUMO band fluctuations.

Molecular mechanism of enhancing antitumor activity through the interaction between monosaccharides and human serum albumin

This study investigated the molecular mechanisms of the interactions between three antitumor active monosaccharides and human serum albumin (HSA) using spectroscopic and electrochemical analyses, supplemented by molecular docking simulations. The antitumor efficacy of these monosaccharides can be significantly enhanced by covalent drug coupling, while HSA, with its long half-life and low immunogenicity, provides new opportunities for the development of advanced antitumor drug delivery systems. The results showed that these monosaccharides effectively burst the fluorescence of HSA. Thermodynamic analysis revealed that Fucose undergoes a spontaneous, exothermic process that decreases entropy, while the binding of Mannose and Galactose is entropy-driven. Notably, the addition of these three monosaccharides slightly compacts the structure of HSA, stabilizing its transport and delivery in vivo, with the binding strength categorized as Fucose > Mannose > Galactose. These variations in binding constants explain the differences in efficacy and potential side effects in antitumor therapy. Further studies have shown that the interaction between monosaccharides and HSA improves drug stability and targeting, thereby enhancing antitumor activity. An in-depth study of these interactions may provide new insights into the design and optimization of antitumor drugs and the further development of novel antitumor therapies.

Voltammetric analysis of glycoproteins containing sialylated and neutral glycans at pyrolytic graphite electrode

Recently, it was described that neutral glycans can be distinguished from those containing sialic acid at the mercury electrode after modification with osmium(VI) N,N,N',N'-tetramethylethylenediamine (Os(VI)tem). Our work shows the possibility of studying glycans and glycoproteins at pyrolytic graphite electrodes depending on thepresence of sialic acid. Short glycans, glycans released from glycoproteins, and glycoproteins themselves yielded similar voltammetric responses after their modification by Os(VI)tem. Os(VI)tem modified glycans and glycoproteins produced acouple of cathodic and anodic peaks. Changing peak heights and potentials of glycans and glycoproteins pointed out the presence of sialic acid. These findings could be utilized to improve glycoprotein sensing by chemical modification.

Schiff Base-platinum and ruthenium complexes and anti-Alzheimer properties

This study investigates the effects of Pt and Ru complexes containing a Schiff base with a diimine structure on Alzheimer's disease. The Schiff base (N1E,N2E)-N1,N2-bis(isoquinolin-4-ylmethylene)benzene-1,2-diamine (I) and the novel Pt(II) and Ru(II) complexes (Ia and Ib) were synthesized and characterized using FTIR, NMR (1H, 13C), mass spectrometry, and elemental analyses. Their ability to inhibit amyloid beta (Aβ1-42) aggregation was determined in vitro using the SH-SY5Y cell line. Fluorescence spectroscopy investigated the early aggregation kinetics and dose-dependent characteristics of Aβ1-42 with the complexes. Transmission electron microscopy confirmed the results. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and 1H NMR spectroscopy examined the interaction with Aβ1-16. Electrochemical analysis using square wave voltammetry monitored the interaction with Aβ1-42. The synthesized complexes were active in inhibiting amyloid aggregation at a low molar ratio.

Dual-mode detection of α-fetoprotein using the photothermal effect and peroxidase-like activity of Au@Cu/Cu2O-rGO

α-Fetoprotein (AFP) is widely recognized as an important marker for monitoring hepatocellular carcinoma (HCC), and its monitoring using two different transduction mechanisms is an effective way to avoid the risk of false positives or false negatives. In this paper, Au@Cu/Cu2O-rGO was used as a photothermal converter as well as an actuator to promote the decomposition of hydrogen peroxide (H2O2), which was further designed as a probe for dual-mode detection to quantitatively assess AFP. The composite nanomaterials possessed photothermal conversion efficiencies (η) of up to 54.9 % and catalytically generated signals up to 1.6 times greater, relative to a single material. Based on the generated temperature and current signals, AFP has been sensitively detected in the range of 0.01-100 ng/mL, with limits of detection (LOD) of 5.62 pg/mL and 1.23 pg/mL, respectively. The dual-mode assay combines portability with high accuracy for the detection of human health systems.

Tailoring diamondised nanocarbon-loaded poly(lactic acid) composites for highly electroactive surfaces: extrusion and characterisation of filaments for improved 3D-printed surfaces

A new 3D-printable composite has been developed dedicated to electroanalytical applications. Two types of diamondised nanocarbons - detonation nanodiamonds (DNDs) and boron-doped carbon nanowalls (BCNWs) - were added as fillers in poly(lactic acid) (PLA)-based composites to extrude 3D filaments. Carbon black served as a primary filler to reach high composite conductivity at low diamondised nanocarbon concentrations (0.01 to 0.2 S/cm, depending on the type and amount of filler). The aim was to thoroughly describe and understand the interactions between the composite components and how they affect the rheological, mechanical and thermal properties, and electrochemical characteristics of filaments and material extrusion printouts. The electrocatalytic properties of composite-based electrodes, fabricated with a simple 3D pen, were evaluated using multiple electrochemical techniques (cyclic and differential pulse voltammetry and electrochemical impedance spectroscopy). The results showed that the addition of 5 wt% of any of the diamond-rich nanocarbons fillers significantly enhanced the redox process kinetics, leading to lower redox activation overpotentials compared with carbon black-loaded PLA. The detection of dopamine was successfully achieved through fabricated composite electrodes, exhibiting lower limits of detection (0.12 μM for DND and 0.18 μM for BCNW) compared with the reference CB-PLA electrodes (0.48 μM). The thermogravimetric results demonstrated that both DND and BCNW powders can accelerate thermal degradation. The presence of diamondised nanocarbons, regardless of their type, resulted in a decrease in the decomposition temperature of the composite. The study provides insight into the interactions between composite components and their impact on the electrochemical properties of 3D-printed surfaces, suggesting electroanalytic potential.

A disposable electrochemical magnetic immunosensor for the rapid and sensitive detection of 5-formylcytosine and 5-carboxylcytosine in DNA

5-formylcytosine (5 fC) and 5-carboxylcytosine (5caC) serve as key intermediates in DNA demethylation process with significant implications for gene regulation and disease progression. In this study, we introduce a novel electrochemical sensing platform specifically designed for the sensitive and selective detection of 5 fC and 5caC in DNA. Protein A-modified magnetic beads (ProtA-MBs) coupled with specific antibodies facilitate the immunorecognition and enrichment of these modified bases. Signal amplification is achieved through several chemical reactions involving the interaction between N3-kethonaxl and guanine, copper-free click chemistry for the attachment of dibenzocyclooctyne (DBCO)-Biotin, and the subsequent recognition by streptavidin-conjugated horseradish peroxidase (SA-HRP). The assay's readout is performed on a disposable laser-induced graphene (LIG) electrode, modified with the bead-antibody-DNA complex in a magnetic field, and analyzed using differential pulse voltammetry in a system employing hydroquinone (HQ) as the redox mediator and H2O2 as the substrate. This immunosensor displayed excellent sensitivity, with detection limits of 14.8 fM for 5 fC across a 0.1-1000 pM linear range and 87.4 fM for 5caC across a 0.5-5000 pM linear range, and maintained high selectivity even in the presence of interferences from other DNA modifications. Successful application in quantifying 5 fC and 5caC in genomic DNA from cell extracts, with recovery rates between 97.7% to 102.9%, underscores its potential for clinical diagnostics. N3-kethoxal was used for the first time in an electrochemical sensor. This work not only broadens the toolkit for detecting DNA modifications but also provides a fresh impetus for the development of point-of-care testing (POCT) technologies.

A portable magnetic electrochemical sensor for highly efficient Pb(II) detection based on bimetal composites from Fe-on-Co-MOF

The practical, sensitive, and real-time detection of heavy metal ions is an essential and difficult problem. This study presents the design of a unique magnetic electrochemical detection system that can achieve real-time field detection. To enhance the electrochemical performance of the sensor, Fe2O3@C-800, Co/CoO@/C-600, and CoFe2O4@C-600 magnetic composites were synthesized using three MOFs precursors by the solvothermal method. And the morphology structure and electrochemical properties of as-prepared magnetic composites were researched by X-ray diffraction (XRD), Scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM), specific surface area and porosity analyzer (BET) and differential pulse voltammetry (DPV). The results shown that these composites improve conductivity and stability while preserving the MOFs basic frame structure. Compared with the monometallic MOFs-derived composites, the synergistic effect of the bimetallic composite CoFe2O4@C-600 can significantly enhance the electrochemical performance of the sensor. The linear range for the detection of lead ions was 0.001-60 μM, and the detection limit was 0.0043 μM with a sensitivity of 22.22 μA μM·cm-2 by differential pulse voltammetry. The sensor has good selectivity, stability, reproducibility and can be used for actual sample testing.

TiO2-guanine as a new amalgamation compound for fabrication of a disposable biosensor with high sensitivity and rapid detection of H1N1 swine flu virus

A TiO2-guanine nanocomposite (TG NC)-based electrochemical biosensor was immobilized with hemagglutinin (HA) gene specific probe with 5' NH2 group on screen-printed gold electrode (probe(ss)DNA-TG-SPGE). The modified biosensor was examined for H1N1 swine flu virus. TG NCs along with precursors were characterized spectroscopically and morphologically by employing several approaches. Electrochemical investigations were performed with the help of cyclic voltammetric (CV) and electrochemical impedance spectroscopy (EIS) in 0.1 M phosphate buffer saline (PBS; pH 7.4) with 1 µM methylene blue (MB) redox indicator. For better detection of single-stranded virus DNA, the modified electrode was optimized at various concentrations, pH, and scan rates. The modified biosensor showed high sensitivity (40.32 μA/ng.cm2), low LOD (0.00024 ng/6 µL), and broad linear range 0.0002-20 ng/6µL with coefficient of determination of R2=0.9981 for H1N1 virus detection. The HA gene-modified biosensor presented decent stability and specificity against different infectious pathogens including H3N2 virus and human DNA with negative response. Furthermore, the modified biosensor also responded well for real sample target DNA detection with a recovery of >96%. The simply designed HA gene-modified biosensor transduces decreased current response towards target-specific (ss)DNA binding and could be used as a rapid detection tool for H1N1 swine flu virus diagnosis.

Water-soluble chitosan salt as ecofriendly corrosion inhibitor for N80 pipeline steel in artificial sea water: Experimental and theoretical approach

Chitosan, as a proficient biopolymer, has enormous potential as an ecofriendly corrosion inhibitor (CI), but their limited solubility restricts practical applications. Herein, an eco-friendly and water-soluble chitosan salt (CS) was utilized as a green CI on N80 pipeline steel in artificial sea water. Several structural and surface analytical tools were engaged in describing the characteristics of novel CS polymer. The corrosion inhibition efficiencies of CS on steel at different concentrations were investigated through gravimetric, conventional and advanced electrochemical techniques along with the surface analyses. Tafel polarization tests specified that CS performed as mixed-type CI with prevalent anodic inhibition characteristics. At a concentration of 1000 ppm, CS provided an inhibition efficiency (IE) of 96.68 %, following physiochemical adsorptions of CS on N80 surface validated by fitting Langmuir adsorption isotherm. However, the reductions in the values of IE at high temperature specified that the CS is the temperature dependent CIs. Scanning electrochemical microscopic evaluation confirmed the formation of thin CS inhibitors films with high electrochemical stability on N80 steel in saline. The performed surface characterizations on inhibited surfaces validated the adsorption of CS on the N80 surface by forming thin inhibitor film to obstruct metal corrosion. The theoretical simulation studies using molecular dynamics and density functional theory corroborated the experimentally obtained results.

Revealing the solid-solution interface interference behaviors between Cu2+ and As(III) via partial peak area analysis of simulations and experiments

The mutual interference in the sensing detection of heavy metal ions (HMIs) is considerably serious and complex. Besides, the co-existed ions may change the stripping peak intensity, shape and position of the target ion, which partly makes peak current analysis inaccurate. Herein, a promising approach of partial peak area analysis was proposed firstly to research the mutual interference. The interference between two species on their electrodeposition processes was investigated by simulating different kinetics parameters, including surface coverage, electro-adsorption, -desorption rate constant, etc. It was proved that the partial peak area is sensitive and regular to these interference kinetics parameters, which is favorable for distinctly identifying different interferences. Moreover, the applicability of the partial peak area analysis was verified on the experiments of Cu2+, As(III) interference at four sensing interfaces: glassy carbon electrode, gold electrode, Co3O4, and Fe2O3 nanoparticles modified electrodes. The interference behaviors between Cu2+ and As(III) relying on solid-solution interfaces were revealed and confirmed by physicochemical characterizations and kinetics simulations. This work proposes a new descriptor (partial peak area) to recognize the interference mechanism and provides a meaningful guidance for accurate detection of HMIs in actual water environment.

PD-L1 DNA aptamers isolated from agarose-bead SELEX

Increased expression and activity of the PD-L1/PD-1 pathway suppresses the activation of cytotoxic T cells, which is vital in anti-tumour defence, allowing tumours to rise, expand and progress. Current strategies using antibodies to target PD-1/PD-L1 have been very effective in cancer therapeutics and companion diagnostics. Aptamers are a new class of molecules that offer an alternative to antibodies. Herein, the systematic evolution of ligands by exponential enrichment (SELEX) using agarose slurry beads was conducted to isolate DNA aptamers specific to recombinant human PD-L1 (rhPD-L1). Isolated aptamers were sequenced and analysed using MEGA X and structural features were examined using mFold. Three aptamer candidates (P33, P32, and P12) were selected for evaluation of binding affinity (dissociation constant, Kd) using ELONA and specificity and competitive inhibition assessment using the potentiostat-electrochemical method. Among those three, P32 displayed the highest specificity (8 nM) against PD-L1. However, P32 competes for the same binding site with the control antibody, 28-8. This study warrants further assessment of P32 aptamer as a potential, cost-effective alternative tool for targeting PD-L1.

The comparative study by Raman spectroscopy of the plastic tide in the three ports of the Mediterranean Sea

This paper summarizes the field studies on marine microplastics (MPs) carried out in the autumn season in four various localisations within three ports chosen at the Mediterranean Sea near the French Riviera and the West Coast of Italy (within the Ligurian Sea). It considers the transport problem and the fate of the MPs introduced to the sea by analysing beach debris found on the shore after the stormy weather. Monitored ports included Saint-Tropez, Portoferraio and Porto Ercole, in which two different places were monitored. The aim is to approach the plastic tide phenomena by concentrating on a selected fraction of all MPs presented on the seashore. The final identification of debris was performed using Raman spectroscopy, providing a high-resolution signal. The PE, PP and PS contents were compared as the most frequent and representative polymers. Finally, we tackle the pending issue of the compound leakage from the MPs taking the environmentally aged particles from Portoferraio for further laboratory experiments and discuss an innovative approach with a low detection limit based on the electrochemical methods.

A wearable sensor based on janus fabric upon an electrochemical analysis platform for sweat glucose detection

Wearable sweat sensing devices have drawn much attention due to their noninvasive and portable properties, which is emerging as a promising technology in daily healthiness assessment issues. A sweat sensor based on Janus fabric and electrochemical analysis is proposed in this work. Unidirectional moisture transported behavior of the Janus fabric serves as the quick-drying component directly contacting skin to transfer sweat toward the detection site. The working electrode was treated by repeated activation of Prussian blue followed by chitosan/single-wall carbon nano tubes/glucose oxidase deposition, ensuring the high electrochemical activity and sensitivity to detect the sweat glucose level. A detection system was established based on the electrochemical analysis of this sweat sensor, which can provide accurate glucose level in the testing samples. The limit of detection (LOD) of the sensor for glucose was 15.32 μM (S/N = 3) and the sensitivity was 3.35 μA/mM. One male subject wears this sensor for intermittent intensity training, outputting the real-time changes in sweat glucose levels, which is consistent with the energy consumption and metabolic status during human exercise. And the sweat glucose level for different subjects was tested to be 35-135 μM, which is coincident with the distribution range of normal human sweat glucose levels.

Diagnosis of acute myocardial infarction: highlighting cardiac troponins as vital biomarkers

The molecular marker, cardiac troponin (cTn) is a complex protein that is attached to tropomyosin on the actin filament. It is an essential biomolecule in terms of the calcium-mediated regulation of the contractile apparatus in myofibrils, the release of which is an indication of the dysfunction of cardiomyocytes and hence the initiation of ischemic phenomena in the heart tissue. Fast and accurate analysis of cTn may help the diagnosis and management of acute myocardial infarction (AMI), for which electrochemical biosensors and microfluidics devices can be of great benefit. This editorial aims to highlight the importance of cTn as vital biomarkers in AMI diagnosis.

Review on recent advancements in the role of electrolytes and electrode materials on supercapacitor performances

Supercapacitors currently hold a prominent position in energy storage systems due to their exceptionally high power density, although they fall behind batteries and fuel cells in terms of energy density. This paper examines contemporary approaches aimed at enhancing the energy density of supercapacitors by adopting hybrid configurations, alongside considerations of their power density, rate capability, and cycle stability. Given that electrodes play a pivotal role in supercapacitor cells, this review focuses on the design of hybrid electrode structures with elevated specific capacitance, shedding light on the underlying mechanisms. Factors such as available surface area, porosity, and conductivity of the constituent materials significantly influence electrode performance, prompting the adoption of strategies such as nanostructuring. Additionally, the paper delves into the impact of novel bio-based hybrid electrolytes, drawing upon literature data to outline the fabrication of various hybrid electrode materials incorporating conducting polymers like polyaniline and polypyrrole, as well as metal oxides, carbon compounds, and hybrid electrolytes such as ionic liquids, gel polymers, aqueous, and solid polymer electrolytes. The discussion explores the contributions of different components and methodologies to overall capacitance, with a primary emphasis on the mechanisms of energy storage through non-faradic electrical double-layer capacitance and faradaic pseudo-capacitance. Furthermore, the paper addresses the electrochemical performance of hybrid components, examining their concentrations and functioning via diverse charge storage techniques.

Graphene/metal-organic framework nano-sandwiches derived N, P-codoped porous carbon nanosheets as robust material for electrochemical analysis

Construction of novel two-dimensional porous carbon nanosheets with superior electrochemical activity is of great challenge. Here, graphene/ZIF-8 nano-sandwiches derived N, P-codoped porous carbon nanosheets (N, P-codoped PCN) was easily obtained by sequential room temperature self-assembly and high-temperature carbonization method. Relative to the widely used physically exfoliated graphene nanosheets (GN) and graphene/ZIF-8 derived N-doped porous carbon nanosheets (N-doped PCN), N, P-codoped PCN displayed larger active surface, faster electron transport ability and stronger physical adsorption ability, which can be ascribed to the dual doping effect of heteroatoms N and P. As a result, N, P-codoped PCN exhibited remarkable oxidation signal enhancement for tumor marker (8-hydroxy-2'-deoxyguanosine), analgesic and antipyretic drug (acetaminophen) and organic pesticide (benomyl). Besides, the limits of detection were measured as low as 1.58 nM, 7.50 nM and 2.10 nM with sensitivity of 270.00 μA μM-1 cm-2, 757.14 μA μM-1 cm-2 and 272.86 μA μM-1 cm-2 for 8-hydroxy-2'-deoxyguanosine, acetaminophen and benomyl, respectively. Basing on this, a novel and highly sensitive electrochemical sensing platform was developed. It is believed that the reported two-dimensional N, P-codoped PCN with unique structure and composition is highly valuable for the development of carbon-based electrochemical sensors.

Self-validating photothermal and electrochemical dual-mode sensing based on Hg2+ etching Ti3C2 MXene

Mercury ions can cause serious damage to the ecological environment, and it is necessary to develop reliable and elegant mercury ion sensors. In this protocol, a label-free photothermal/electrochemical dual-mode strategy for Hg2+ is proposed based on delaminated Ti3C2 MXene nanosheets (DL-Ti3C2 MXene). Hg2+ exists in water in the form of HgCl2, Hg(OH)2, and HgClOH, and the electron-rich elements O and Cl can specifically bind to the positively charged DL-Ti3C2 MXene at the edge, and further oxidation-reduction reaction occurs to obtain TiO2/C and Hg2Cl2. In view of the reduction activity and the performance of photothermal conversion of DL-Ti3C2 MXene itself, the electrochemical and photothermal responses decrease with the increase of the logarithm of Hg2+ concentration. The corresponding linear ranges are 50 pmol L-1-500 nmol L-1 and 1 nmol L-1-50 μmol L-1, and their detection limits calculated at 3 S/N are 17.2 pmol L-1 and 0.43 nmol L-1, respectively. DL-Ti3C2 MXene has the characteristics of a wide range of raw materials, low cost, and easy preparation. In addition, the design takes full advantage of the properties of the material itself, avoids the complex assembly and detection process of conventional sensors, and enables high selectivity and sensitivity for mercury detection. In particular, the dual-mode sensing endows self-confirmation of mercury ion detection results, thereby improving the reliability of the sensor.

Heterojunction and vacancy engineering strategies and dual carbon modification of MoSe2-x@CoSe2-C /GR for high-performance sodium-ion batteries and hybrid capacitors

Sodium-ion batteries (SIBs) and hybrid capacitors (SIHCs) have great potential in related electrochemical energy storage fields. However, the inferior cycling performance and sluggish kinetics of Na+ transport in conventional anodes continue to impede their practical applications. Here, we propose a refined design by utilizing well-organized MoSe2 nanorods as precursors and introducing a metal-organic framework and graphene (GR), while resulting in the formation of bimetallic selenide heterostructures/carbon MoSe2-x@CoSe2-C/GR (MCCR) composite through electronegativity. The MoSe2-x/CoSe2 heterostructure can spontaneously form the built-in electric field to accelerate the charge transport, and the formation of anionic Se vacancies induced by electronegativity in situ can provide more active sites for enhancing sodium storage. The presence of external carbon and graphene can act as buffer layers to suppress the volume expansion of MoSe2-x/CoSe2 heterogeneous, and on the other hand, form a conductive network externally to improve electrode conductivity. As anticipated, the MCCR electrode demonstrates superior reversible specific capacity (446 mAh g-1 after 100 cycles) and substantial pseudocapacitance contribution, excellent rate performance in SIB half and full cells. In addition, system electrochemical analysis of multiple ex-situ characterizations elucidates the electrochemical reaction kinetics and transformation mechanism of MCCR electrodes during charging and discharging in depth. When coupled with activated carbon (AC), the MCCR//AC SIHC full hybrid capacitors exhibit impressive cycling stability over 2500 cycles at 1 A g-1 and excellent rate performance, demonstrating their widespread application in energy storage.