The electrochemical properties of a CFX cathode were improved by defluorination of the surface with a N2 plasma and using a silica wafer. Compared to the N2 plasma treatment alone, when the CFX and silica were reacted together, the C-F bonds were modified and the surface was etched efficiently, so defluorination was enhanced. An electrochemical analysis confirmed that Half-cells prepared by treating CFx and silica with nitrogen plasma exhibited a capacity of about 400 mAh/g at 5C. In addition, it was confirmed that the loss of charge transfer was reduced by up to 71% compared to that for pristine CFX. As shown by a GITT analysis, when the CFx and silica were treated with N2 plasma together, the ion conductivity gradually increased due to a decrease in the ion diffusion barriers and the formation of a carbon layer. Therefore, this is a simple and effective way to improve the conductivities of CFX cathode materials with the energy of a N2 plasma and the silica-fluorine reaction.

pH plays a pivotal role in influencing various aspects of proton-coupled electron transfer (PCET) reactions in electrochemical systems. These reactions are affected by pH in terms of mass transport, electrochemical double layer (EDL) structure, and surface adsorption energy, all of which impact the overall electrochemical processes. This review article aims to provide a comprehensive understanding of the research progress made in elucidating the effects of pH on different electrochemical reactions, the hydrogen evolution reaction/hydrogen oxidation reaction (HER/HOR), oxygen reduction reaction/oxygen evolution reaction (ORR/OER), and carbon dioxide reduction reaction ( CO2RR). To embark on this endeavor, we have conducted a bibliometric analysis to clearly outline of the research trends and advancements in the field concerning the pH effects. Subsequently, we present a systematic overview of the mechanisms governing these reactions, with a special focus on pH’s influence on both the proton and electron aspects. We conclude by discussing the current challenges in this area and suggesting future research avenues that could further our understanding of pH's role in electrochemical reactions.

Flexible self-supported laser-induced graphene (LIG) electrode devices were facilely fabricated through laser ablation technique by employing commercial polyimide film as the precursor material. Compared with the widely used traditional glassy carbon electrodes, the resulted LIG electrodes displayed abundant porous structure and surface defects. Notably, the onestep yielded LIG electrode devices were endowed with large electrochemically active surface area and accelerated electron transfer ability. Benefiting from its superior electrochemical property, these unmodified LIG electrodes exhibited remarkable enhanced electrochemical oxidation reactivity toward the food additive molecule Allura Red. Based on the augmented oxidation signal of Allura Red molecules on the LIG electrodes, a novel electrochemical sensor with high sensitivity for the detection of Allura Red was successfully developed. The sensor demonstrated a linear detection range spanning from 5 nM to 1 μM and exhibited a detection limit as low as 2.5 nM. Besides, the sensitivity was calculated to be 240.62 μA μM−1 cm− 2. More importantly, the sensor manifested outstanding stability, reproducibility, and practicality, further emphasizing its potential for real-world application.

Bortezomib (BTZ) and dasatinib (DA) are two substantial anti-cancer agents with side effects on the human body. In this research, we fabricated a novel electrochemical sensor modified by CuFe2O4/ SmVO4 nanocomposite and 1-ethyl-3-methylimidazolium chloride (1E3MC) as an ionic liquid (IL) ( CuFe2O4/SmVO4/IL/CPE) for coinciding investigation of BTZ and DA for the first time. The CuFe2O4/ SmVO4 synthesized were determined and certified through field-emission scanning electron microscopy (FE-SEM), energy diffraction X-ray (EDX), and X-ray diffraction (XRD). The capability of the sensor was investigated by different electrochemical techniques such as cyclic voltammetry (CV), chronoamperometry (CHA), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). The attained data showed that the oxidation signal of bortezomib and dasatinib promoted as an innovative electrochemical sensor. After optimization of the conditions using this sensor at pH 7.0, the oxidation signal of bortezomib and dasatinib showed to be linear with drug concentrations in the range of 0.09–90 μM and 100–500 μM with a detection limit of 5.4 nM and 7.0 μM, respectively, using differential pulse voltammetry method. The values of D and electro-transfer coefficient (α) achieved 2.5 × 10− 5 cm2 s− 1 and 0.99, respectively. The proposed electrochemical sensor exhibited acceptable selectivity and sensitivity for simultaneous detection of bortezomib and dasatinib in pharmaceutical and biological samples.

Accurate and rapid detection of antibiotics is critical for protecting human health and the environment. To this end, we report a novel electrochemical sensor for the simultaneous detection of Levofloxacin (LFX) and Tryptophan (TRP) in dairy samples. Outstanding electrocatalytic activity for the oxidation of LFX and TRP is exhibited by the Activated Nanodiamond (AND) and Ti3AlC2 max phase ( Ti3AlC2max) nanocomposite-modified glassy carbon electrode ( Ti3AlC2max AND/GCE) featured in our sensor. High selectivity and sensitivity are achieved by the sensor, with limits of detection (LOD) of 20.47 nM and 0.309 μM for LFX and TRP, respectively. Moreover, strong anti-parasite capacity is demonstrated by the developed sensor, making it an excellent candidate for the establishment of a reliable sensing platform for antibiotic detection. Findings suggest that this novel sensor could serve as a valuable tool for monitoring the content of LFX and TRP in dairy samples and enhancing the safety of these products.

Sulfamonomethoxine (SMM) is widely used to inhibit Gram-positive and Gram-negative bacteria, and improper use of SMM is detrimental to human health and ecological stability. Therefore, a sensitive determination method is of great importance for monitoring SMM residues in water, meat, milk, eggs, etc. Herein, a Pt-functionalized S-doped graphitic carbon nitride (Pt/Sg- C3N4) was constructed for the electrochemical determination of SMM. The as-developed Pt3/ S3-g-C3N4 sensor showed a significant SMM determination performance. The electrochemical oxidation of SMM on Pt3/ S3-g-C3N4/GCE involves two electron transference and was limited by a diffusion process. The as-developed Pt3/ S3-g-C3N4/GCE sensor has good linearity in a wide range of 0.1–120 μmol/L and a remarkably low limit of detection (LOD) of 0.026 μmol/L for SMM determination. In addition, the sensor has high selectivity and anti-interference properties for SMM detection. Furthermore, this Pt3/ S3-g- C3N4/GCE sensor has good reproducibility and stability. Moreover, the recoveries were in the range of 89.6–112.2% for the detection of the SMM in a real sample of egg. The proposed Pt3/ S3-g-C3N4/GCE sensor shows great potential for practical applications in detecting trace amounts of antibiotics.

Determination of Idarubicin (IDA) as an anthracycline derivative and extensively used treatment of leukemia was investigated by electrochemical method using carbon paste electrode (CPE) modified with NiO/SWCNTs nanocomposite and 1-ethyl-3-methylimidazolium chloride (EMCl). The NiO/SWCNTs nanocomposites and EMCl play an important catalytic role in improving the electron transfer process at surface of CPE to monitoring of IDA. Electrochemical method was used to investigation redox behavior of IDA at surface of the NiO/SWCNTs/EMCl/CPE. The oxidation signal of IDA amplified by modification of CPE by NiO/SWCNTs and EMCl was about 4.3 times and NiO/SWCNTs/EMCl/CPE detected IDA in concentration range of 0.001–160 μM with detection limit of 0.5 nM, respectively. The evaluation of analytical and recovery data confirms the mentioned method was completely validated and successfully employed for the determination of IDA in real samples.

This paper presents an electrochemical immunosensor using a graphene/multi-walled carbon nanotube (MWCNT) composite platform for detecting the cardiovascular marker C-reactive protein (CRP). The immunosensor exhibited a linear detection range of 0.20–100 ng/mL CRP with a low limit of detection reaching 0.081 ng/mL. The composite material provided a 3D porous structure that allowed efficient antibody immobilization and minimized steric hindrance. The sensor showed high specificity, with minimal response to interfering substances. Using differential pulse voltammetry, the immunosensor demonstrated exceptional precision, rapid detection, and a direct correlation between CRP concentration and sensor response current. Overall, this work highlights the potential of the graphene/MWCNT composite platform as a robust tool for early CRP detection and cardiovascular disease risk assessment. The immunosensor provides sensitive and selective CRP quantification that could enable timely clinical intervention for at-risk individuals.

This study reports the synthesis of a novel graphene/chitosan/β-cyclodextrin composite material (GO/CS/β-CD) via a onestep chemical reduction method, which combines the advantages of graphene, chitosan, and β-cyclodextrin. The morphology and structure of the composite were characterized using various techniques, such as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy. Subsequently, sortase A (SA) was immobilized onto the GO/CS/β-CD for the detection of Staphylococcus aureus. The sensor exhibited a good linear relationship within the concentration range of 30–300 CFU/mL, with a detection limit of 12 CFU/mL. The GO/CS/β-CD composite material showed enhanced properties due to the synergistic effect of graphene, chitosan, and β-cyclodextrin. The immobilization of sortase A onto the composite material improved the sensitivity and selectivity of the sensor for the detection of S. aureus. This study presents a novel graphene/chitosan/β-cyclodextrin composite material with immobilized sortase A, demonstrating enhanced sensitivity and selectivity for the detection of Staphylococcus aureus, which has potential for the development of high-performance sensors in various fields.

In this paper, a simple, cost-effective, and efficient electrochemical sensor for molecular imprinting melatonin was established. The molecular imprinted films were formed by in situ electrochemical polymerization using molecular imprinting technology. The modification method, modification time and other parameters of the electrode were optimized. Under optimized conditions, the sensor responds to melatonin concentration in a linear range of 0–100 μM. The detection limit was 0.171 μM. In addition, the sensor has little response to interfering substances, such as uric acid, vitamin B6, vitamin C, and glucose, and can be tested in real samples. The recoveries were 98.73–101.60%.

Zeolitic imidazolate frameworks (ZIFs) along with carbon nanofibers and polyaniline composite have been explored as an electrochemical sensing platform in nitrite measurement at trace level. Owing to their topology, high surface area and porous structure, these metal–organic frameworks (MOFs) find widespread utility in different application domains. Nitrites are widely used as preservatives in dairy, meat products, and packaged food stuffs. They form N-nitrosamines, which are potential carcinogens and cause detrimental health effects. These ZIF-based MOFs along with carbon nanofibers and polyaniline have emerged as an efficient electrochemical sensing material. The composite has been characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and BET surface area studies. The electrochemical performance of the composite has been evaluated by forming as a thin film of composite on the surface of glassy carbon electrode and studying its impedance as well as electrochemical sensing behavior. The sensor exhibited good analytical response in nitrite measurement with a limit of detection of 8.1 μM. The developed sensing platform has been successfully applied to quantify the nitrite levels from water samples. The results obtained are in good agreement with the results of standard protocol.

Environmental pollution has become an alarming issue for the modern world due to the extensive release of untreated chemical waste into freshwater bodies. Untreated chemical waste poses significant negative impacts on aquatic life and human health. The phenolic compounds are widely used in different industries for dyeing, as food preservatives, and for the production of pesticides. 2,4,6-Trichlorophenol (TCP) is among the most hazardous phenolic compounds that cause several serious health effects. Thus, it is important to monitor TCP in the environmental samples frequently. In the current work, it was aimed to develop a highly sensitive zinc oxide-doped (ZnO) reduce graphene oxide (rGO) composite-based electrochemical sensor for TCP monitoring in the real samples. In this regard, graphene oxide (GO) was simultaneously reduced and doped with ZnO using a facile microwave-assisted synthesis strategy. The resulting ZnO/rGO composite was successfully utilized to fabricate ZnO/rGO-modified glassy carbon electrode (ZnO/rGO/GCE) for the selective and trace level determination of TCP. The conductivity and electrocatalytic behaviors of ZnO/rGO/GCE were examined through different modes of electrochemical setup. Under the optimal operating conditions such as a scan rate of 80 mV.s−1, PBS electrolyte (pH 7.0), and the concentration range of 0.01–80 μM, the fabricated electrochemical sensor manifested outstanding responses for monitoring TCP. The limit of detection (LOD) and limit of quantification (LOQ) of the ZnO/rGO/GCE for TCP were found as 0.0067 μM and 0.019 μM, respectively. Moreover, the anti-interference profile and stable nature of ZnO/rGO/GCE made the suggested electrochemical sensor a superb tool for quantifying TCP in a real matrix.

Oxygen-rich porous carbon is of great interest for energy storage applications due to its improved local electronic structures compared with unmodified porous carbon. However, a tunable method for the preparation of oxygen-rich porous carbon with a special microstructure is still worth developing. Herein, a novel modification of porous carbon with different microstructures is facilely prepared via low-temperature solvothermal and KOH activation methods that employ the coal tar and eight substances, such as cellulose as carbon source and modifier, respectively. By testing the yield, surface group structure, lattice structures, morphology, thermal weight loss, and specific capacitance of carbonaceous mesophase, cellulose–hydrochloric acid is identified as the additive for the preparation of oxygen-rich coal tar-based porous carbon. The obtained porous carbon displays a specific surface area of up to 859.49 m2 g− 1 and an average pore diameter of 2.39 nm. More importantly, the material delivers a high capacity of 275.95 F g− 1 at 0.3 A g− 1 and maintains a high capacitance of 220 F g− 1 even at 10 A g− 1. When in a neutral electrolyte, it can still retain a reversible capacity of 236.72 F g− 1 at 0.3 A g− 1 and 136.79 F g− 1 at 10 A g− 1. This work may provide insight into the design of carbon anode materials with high specific capacity.

Achieving cost-effective and defect-free graphene sheets is highly desirable for sensor devices. Aiming this, few-layer graphene (~ 3) sheets are prepared by an electrochemical exfoliation with [NMP] [ HSO4] electrolyte (i.e., Bronsted acidic ionic liquid). A novel approach for the effective exfoliation of graphene sheets is demonstrated by (i) simultaneously applying a constant potential through an electrochemical cell (with different electrolyte concentrations) and (ii) together with sonication. The exfoliated graphene sheets are characterized through state-of-the-art techniques and sprayed on a glass substrate at optimum conditions. Thus, the transparent conducting sensor device is fabricated with a suitable contact electrode and used for ammonia vapor sensing and the sensor performances are highly dependent on the concentration of the ionic liquid used during the electrochemical exfoliation. The sensing response and limit of detection for the exfoliated graphene-based film were calculated as 3.56% and 432 ppb, respectively. Further studies indicated that the fabricated sensors are more selective towards ammonia molecules with quick response and recovery times.

The nanostructured dysprosium oxide ( Dy2O3) was synthesized by the co-precipitation method and incorporated with graphitic carbon nitride (g-C3N4) using the ultrasonication method. The resultant product is denoted as Dy2O3/ g-C3N4 nanocomposite which was further used for electrochemical sensing of riboflavin (RF). The physicochemical properties of Dy2O3/ g-C3N4 nanocomposite were examined using several characterization techniques. The obtained results exhibit the nanocomposite formation with the preferred elemental compositions, functional groups, crystalline phase and desired surface morphology. The electrocatalytic performance of Dy2O3/ g-C3N4 nanocomposite was scrutinized with a glassy carbon electrode (GCE) via differential pulse voltammetry (DPV) and cyclic voltammetry (CV) techniques with the conventional three-electrode system. The modified electrode distributes more active surface area suggesting high electrocatalytic activity for the RF detection with two linear ranges (0.001–40 μM and 40–150 μM), a low detection limit of 48 nM and sound sensitivity (2.5261 μA μM−1 cm− 2). Further, the designed sensor possesses high selectivity, excellent stability, repeatability and reproducibility. Finally, the fabricated sensor was successfully estimated for the detection of RF in actual food sample analysis using honey and milk with better recovery.

Black phosphorus (BP) is incorporated in the electrochemical detection of uric acid (UA) to form few layers of BP nanosheets (BPNS)-modified glassy carbon electrodes (BPNS/GCE), investigated by means of ultrasound-assisted liquid-phase exfoliation. We find a significant increase in the peak current magnitude and positive potential shift in the electrochemical response of BPNS/GCE, which may be attributed to the larger specific surface area and good charge transfer ability of BPNS. Further, the electrochemical response of BPNS/GCE is evaluated under different conditions to achieve the optimal conditions. UA detection using differential pulse voltammetry (DPV) shows linear response within the range of 1–1000 μM with a detection limit of 0.33 μM. This work reveals new applications of BP nanomaterials in the electrochemical sensing, thereby promoting further advancement in terms of practical applications of two-dimensional nanomaterials.