Linear Scan Voltammetry Research Articles

Synthesis of New 1,4-Naphthoquinone Fluorosulfate Derivatives and the Study of Their Biological and Electrochemical Properties.

This study presents the synthesis of new fluorosulfate derivatives of 1,4-naphthoquinone by the SuFEx reaction. Anticancer properties of obtained compounds were studied on PC-3 (prostate adenocarcinoma), SKOV-3 (ovarian cancer), MCF-7 (breast cancer), and Jurkat cell lines. All the studied compounds showed higher cytotoxic effects than Cisplatin. The DFT method was applied to determine the electronic structure characteristics of 1,4-naphthoquinone derivatives associated with cytotoxicity. A method of determination of 2,3-dichloro-1,4-naphthoquinone (NQ), 3-chloro-2-((4-hydroxyphenylamino)-1,4-naphthoquinone (NQ1), and 4-((3-chloro-1,4-naphthoquinon-2-yl)amino)phenyl fluorosulfate (NQS) in a pharmaceutical substance using an impregnated graphite electrode (IMGE) was developed. The morphology of the IMGE surface was studied using scanning electron microscopy (SEM). The electrochemical behavior of NQ, NQ1, and NQS was studied by cyclic voltammetry (CV) in 0.1 M NaClO4 (96% ethanol solution) at pH 4.0 in a potential range from -1 to +1.2 V. Electrochemical redox mechanisms for the investigated compounds were proposed based on the determining main features of the electrochemical processes. Calibration curves were obtained by linear scan voltammetry in the first derivative mode (LSVFD) with the detection limit (LOD) 7.2 × 10-6 mol·L-1 for NQ, 8 × 10-7 mol·L-1 for NQ1, and 8.6 × 10-8 mol·L-1 for NQS, respectively.

Enhancing the anodic dissolution uniformity of dendritic-structured refractory high entropy alloys using a split electrolytic cell with a deep eutectic solvent

The attainment of uniform anodic dissolution in dendritic-structured refractory high entropy alloys (RHEAs) during the electropolishing process is essential for their utilization in high-precision components. Nevertheless, the intricate microstructures of these materials impede uniform dissolution, resulting in suboptimal surface quality. In this work, based on a choline chloride-based deep eutectic solvent and suitable polarization parameters selected by linear scanning voltammetry, a split electrolytic cell (SEC) was proposed to alter the traditional integrated electrolytic cell (IEC) to enhance the anodic dissolution uniformity of dendritic-structured RHEAs. A much smoother surface with Ra of 0.233 μm and a smaller height discrepancy of 0.8 μm was obtained, compared to those processed in IEC at the same condition. The non-uniform anodic dissolution was mainly attributed to the cathode-forming (hydroxide ion (OH−), dissolution of tungsten (W) in the dendrite region under the attack by OH−, and the formation of by-product, i.e., the water molecule. The positive impact of SEC on dissolution uniformity could be ascribed to its role in inhibiting OH− from interacting with the anode, as well as to the enhancement of solution acidity on the anode side, which facilitated the dissolution of metal oxides. The suggested reaction pathway was subsequently validated through experiments with controlled water concentration and assessing of electrochemical kinetics. Finally, the effects of SEC under different parameters were demonstrated. This work provides valuable insight into the precise, micro/nanoscale manufacturing and green electrochemical surface finishing of RHEAs in the future.

Improving photoelectrochemical performance of transferred TiO2 nanotubes onto FTO substrate with Mo2C and NiS as Co-catalyst

The photoelectrochemical (PEC) performance of titanium dioxide nanotube (TiO2 NT) photoelectrodes for sustainable hydrogen production has garnered significant research interest. Despite the advantages of TiO2 NT fabricated via anodization of titanium metal, such as their well-ordered vertical structure, challenges persist including the thick oxide barrier layer, limited optical transparancy, and the wide energy band gap (∼3.0 eV), which constrain their practical efficiency in PEC applications. This study addresses these limitations by introducing a novel approch to transfer TiO2 NT onto a fluorine-doped tin oxide (FTO) substrate. TiO2 NTs were synthesized with varying anodization times and steps to achieve optimal free-standing structures. To further enhance PEC performance, co-catalyst including molybdenum carbide (Mo2C) and nickel sulfide (NiS) were incorporated using immersion and successive ionic layer adsorption reaction (SILAR) methods, respectively. Comprehensive characterization using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), ultraviolet–visible–near infrared (UV–Vis–NIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS) provided insights into the crystal phase, morphological structure, band gap, and elemental composition of the photoelectrodes. Photoelectrochemical and photostability evaluations were conducted through linear scan voltammetry (LSV) and chronoamperometry under dark and light conditions. Results indicate that transferring TiO2 NTs onto FTO significantly enhanced photocurrent density, achieving a 2.5-fold increase at 0.7 V versus a TiO2 NT/Ti substrate. The incorporating of co-catalysts Mo2C, NiS and the combined NiS/Mo2C further enhanced the photocurrent density to 2.20, 3.00 and 8.00 mA cm−2 respectively, with a remarkable 31-fold enhancement compared to the TiO2 NT/Ti substrate. This findings underscore the potential of the TiO₂ NT/FTO photoelectrode with optimized co-catalyst integration for advanced photoelectrochemical applications.

Understanding the Effect of Lithium Nitrate as Additive in Carbonate-Based Electrolytes for Silicon Anodes

Due to its high specific capacity, silicon is one of the most promising anode materials for next-generation lithium-ion batteries. However, its large volumetric changes upon (de)lithiation of ∼300% lead to a rupture/re-formation of the solid-electrolyte interphase (SEI) upon cycling, resulting in continuous electrolyte consumption and irreversible loss of lithium. Therefore, it is crucial to use electrolyte systems that form a more stable SEI that can withstand large volume changes. Here, we investigate lithium nitrate (LiNO3) and lithium nitrite (LiNO2) as electrolyte additives. Linear scan voltammetry on carbon black working electrodes in a half-cell configuration with LiNO3-containing 1 M LiPF6 in EC/DEC (1/2 v/v) revealed a two-step reduction mechanism, whereby the first reduction peak could be attributed to the conversion of LiNO3 to LiNO2, while X-ray photoelectron spectroscopy on harvested electrodes suggests the formation of Li3N during the second reduction peak. On-line electrochemical mass spectrometry (OEMS) on carbon black electrodes showed that N2O gas is evolved upon the reduction of LiNO3- and LiNO2-containing electrolytes but that the gassing associated with EC reduction is significantly reduced. Furthermore, OEMS and voltammetry were used to examine the redox chemistry of LiNO2 additive. Finally, LiNO3 and LiNO2 additives significantly improved the cycle-life of Si||NCM622 full-cells.

Novel electrochemical sensor based on MoS2NSs@AgNPs/MWCNTs-COOH nanocomposites for effective detection of Penciclovir

Abnormal levels of penciclovir (PCV) in humans may lead to inflammation and renal impairment, and its frequent detection in the aquatic environment poses environmental hazards. Consequently, timely detection and regulation of PCV concentrations in the human body are crucial for drug research, disease diagnosis, and environmental protection. In this study, a PCV electrochemical sensing platform based on MoS2NSs@AgNPs/MWCNTs-COOH was constructed by in situ reduction of silver nanoparticles (AgNPs) on MoS2 nanosheets (MoS2NSs) and complexed with carboxylated multi-walled carbon nanotubes (MWCNTs-COOH). The synergistic effect of highly conductive AgNPs, high surface area MoS2NSs, and MWCNTs-COOH increased the electron transfer rate at the electrode surface and thus effectively promoted the electrooxidation process of PCV. The electrochemical performance of the sensor was investigated and optimized by cyclic voltammetry (CV) and linear scanning voltammetry (LSV). The linear response of PCV under optimal conditions was in the range of 0.5–200.0 µM, with a limit of detection (LOD) of 0.039 µM (S/N = 3), and recoveries of 98.1–101.1 %, 95.6–101.6 %, 97.0–103.6 %, and 96.0–100.9 %. The results show that the constructed MoS2NSs@AgNPs/MWCNTs-COOH /GEC sensing platform has the advantages of high sensitivity, fast response speed, and strong anti-interference ability. This work is the first to develop an electrochemical sensing platform for PCV based on MoS2NSs@AgNPs/MWCNTs-COOH, providing a new PCV quantitative detection solution.

Riboflavin derivatives as a novel electron transfer mediator for enhancing Cr(VI) removal by Shewanella oneidensis MR-1

Bioremediation has garnered considerable interest due to its advantages of economy and no secondary pollution. However, the direct electron transfer rate between microorganisms and Cr(VI) is low. The bioreduction of Cr(VI) by Shewanella oneidensis MR-1 (S. oneidensis) in the presence of formylmethylflavin (FMF) was conducted to understand how FMF mediated the extracellular electron transfer process to improve Cr(VI) removal. In this study, FMF was firstly synthesized by modifing RF to increase its solubility and redox activity. The findings indicate that S. oneidensis/FMF exhibited better Cr(VI) removal performance compared to that of S. oneidensis. Under optimum conditions, 40 mg/L Cr(VI) could be completely removed by S. oneidensis/FMF within 120 h, while only 48.6% of Cr(VI) was removed by S. oneidensis, and the first order rate constant (k) for the Cr(VI) elimination by S. oneidensis/FMF (0.033 h−1) was about 4.1-fold greater than that of S. oneidensis (0.008 h−1). Moreover, the removal of Cr(VI) by S. oneidensis/FMF were dominated by reduction, and supplemented by adsorption and complexation. FMF enhance the extracellular electron transfer rate (EETR) was confirmed by electrochemical cyclic voltammetry (CV) and linear scanning voltammetry (LSV) experiments. This study emphasizes the potential important role of FMF in environmental bioremediation.

Bi2MoO6/MWCNTs-COOH/GCE electrochemical probe for ultrasensitively and selectively detecting antibiotic norfloxacin

Antibiotics have emerged as a class of contaminants of concern globally, raising widespread worry and unease, primarily because of their inappropriately use and endless migration in food chains. Electrochemical ultrasensitive and selective determination of norfloxacin (NOR) using bismuth-based bimetallic salt bismuth molybdate (Bi2MoO6) and carboxylated multi-walled carbon nanotube (MWCNTs-COOH) hybrid electrode as sensing platforms is presented hereby. The electrocatalytic ability of the electrodes was verified to be enhanced by the synergy effect of both Bi2MoO6 and MWCNTs-COOH using cyclic voltammetry and electrochemical impedance spectroscopy. Linear scan voltammetry was applied to detect NOR. The oxidation peak current was linearly correlated with NOR concentration of 0.03–10 μM and the low limit detection of the optimized method was 6.7 nM (S/N = 3). In addition, it was verified that Bi2MoO6/MWCNTs-COOH/GCE probe had good stability, reproducibility, repeatability and selectivity. The spiked recovery method for NOR in milk and lake water samples showed recoveries of 94.8 – 96.9% and 90.2 – 98.3%, respectively, which can be used to determine NOR in real samples with high sensitivity. The preparation of Bi2MoO6/MWCNTs-COOH/GCE provides a new prototype for probing NOR detection at nanomolar concentration and safeguarding antibiotic contamination in environmental and food chains.

Inkjet-Printed LSM-YSZ Thin Films for Enhanced Oxygen Electrodes in Solid Oxide Fuel Cells.

In the present work, symmetrical oxide ion conducting solid oxide single cells with inkjet-printed composite LSM-YSZ electrodes, onto commercially available YSZ dense substrates using GDC as buffer interlayer, were fabricated and characterized. Stable inkjet-printable LSM-YSZ nanoparticle inks were developed based on water solvent, after processing with high intensity ball milling. The deposition of LSM-YSZ electrodes was performed by inkjet printing, as well as a conventional additive manufacturing technique, screen printing, in order to compare the electrochemical performance of the produced cells for the reversible charge transfer reaction (O2 + 4 e- ↔ 2 O2-). The physicochemical properties of the LSM-YSZ nanoparticle ink was investigated to determine ink printability. The electrochemical performance of fabricated inkjet-printed and screen printed symmetrical cells (LSM-YSZ | GDC | YSZ | GDC | LSM-YSZ) exposed under a synthetic air atmosphere was evaluated in a single chamber cell reactor, employing the AC impedance spectroscopy and linear scan voltammetry techniques, at the temperature range of 700-850 °C. The inkjet-printed electrodes exhibited highly homogeneous and porous morphologies with the corresponding cell achieving current densities almost five times higher, up to 1 A/cm2 at 2 V cell potential and 850 °C, than those of the equivalent screen-printed one. To the best of our knowledge, this is the first successful implementation of water-based inks of LSM-YSZ electrodes in the fabrication of inkjet-printed solid oxide cells.

Au24Cd Nanoenzyme Coating for Enhancing Electrochemical Sensing Performance of Metal Wire Microelectrodes.

Dopamine (DA), ascorbic acid (AA), and uric acid (UA) are crucial neurochemicals, and their abnormal levels are involved in various neurological disorders. While electrodes for their detection have been developed, achieving the sensitivity required for in vivo applications remains a challenge. In this study, we proposed a synthetic Au24Cd nanoenzyme (ACNE) that significantly enhanced the electrochemical performance of metal electrodes. ACNE-modified electrodes demonstrated a remarkable 10-fold reduction in impedance compared to silver microelectrodes. Furthermore, we validated their excellent electrocatalytic activity and sensitivity using five electrochemical detection methods, including cyclic voltammetry, differential pulse voltammetry, square-wave pulse voltammetry, normal pulse voltammetry, and linear scanning voltammetry. Importantly, the stability of gold microelectrodes (Au MEs) modified with ACNEs was significantly improved, exhibiting a 30-fold enhancement compared to Au MEs. This improved performance suggests that ACNE functionalization holds great promise for developing micro-biosensors with enhanced sensitivity and stability for detecting small molecules.

Marine biocorrosion inhibition of Pseudomonas sp. biofilms on 304 stainless steel coated with poly-6-aminoindole produced by two different electrochemical methods

Forming a bacterial biofilm on a metallic surface could result in biocorrosion and biofouling development. New environmentally friendly coatings are required to protect infrastructure, especially in coastal and marine environments. This study aimed to evaluate the mitigation of biocorrosion produced by Pseudomonas sp. biofilms on AISI 304 stainless steel (SS304) coupons modified with poly-6-aminoindole (PAIn) using two electrochemical techniques: cyclic voltammetry (SS/6-PAIn CV) and chronoamperometry (SS/6-PAIn CA). Experimental trials were performed in two stages: (i) the settlement and colonization of bacteria (1 h of incubation) and (ii) biofilm development (7 days of incubation). Colonized surfaces were characterized by epifluorescence and field emission scanning electron microscopy. Biocorrosion mitigation was evaluated using linear resistance polarization, electrochemical impedance spectroscopy, and linear scanning voltammetry in simulated seawater at 20 °C. The results showed biofilm formation on SS304 and SS/6-PAIn CA, but in SS/6-PAIn CV, the coating considerably reduced biofilm formation, with alterations in the size and structural organization of the biofilm. The biofilm cover percentages were 31.63 %, 22.66 %, and 9.25 % for SS304, SS/6-PAIn CA, and SS/6-PAIn CV, respectively. Thus, SS/6-PAIn CV reduced biofilm growth by 70.76 % compared to bare SS after seven days of culture. Electrochemical parameters determined by LSV and EIS showed a significant improvement in charge transfer resistance and coating resistance for the SS/6-PAIn CV compared to the coating produced by chronoamperometry. Although both coatings protected the metallic surface, SS/6-PAIn CV presented the best protective properties, emerging as a promising alternative coating to mitigate the biocorrosion process of SS304 in a marine environment.

Effects of substrate materials and electrodeposition parameters on hydrogen evolution reaction of Ni–Cu–Fe coatings

In this study, the effects of substrate materials and electrodeposition parameters on the hydrogen evolution reaction (HER) of Ni–Cu–Fe coatings were studied. For this purpose, different materials, including carbon steel (CS), stainless steel 304 (SS), and pure commercial graphite (G) were used as substrates, while the coating process was done in both modes of constant current density (CC) and variable current density, the latter to produce a functionally-graded (FG) coating. Microstructural investigations were done by using scanning electron microscopy, while the HER behavior was analyzed by electrochemical tests, including cyclic voltammetry (CV), linear scanning voltammetry (LSV), and electrochemical impedance (EIS) measurements. The morphology of the produced Ni–Cu–Fe coatings was completely affected by the coating parameters in the deposition bath and the type of substrates. In samples with micro/nano-cone morphology, deposited at a constant current density of 2.5 A/dm2, better HER behavior was obtained due to the highly effective surface and easier separation of hydrogen bubbles. Besides, the best electrocatalytic activity and the lowest overpotential (110 mV at 10 mA/cm2 in CC mode) were related to the samples coated on G. The proper selection of the substrate material plays an important role in improving the electrocatalytic behavior of composite coatings.

One step to direct extracted gold and silver from industrial Cu-Ag-Sb-Au alloy by a convenient bimetallic electrolytic separation process

Cu-Ag-Sb-Au alloy produced from lead anode slime reduction smelting through twice vacuum distillation is a high value-added precious metal resource. Currently, using pyrometallurgical process, the antimony and copper elements can be removed respectively by multistage oxidation refining, and then the precious metals are recycled by electrolytic refining. This process has a number of shortcomings such as high energy consumption, high pollution and low direct yield. In this study, a highly efficient new process for extracting precious metals from Cu-Ag-Sb-Au alloy by one-step bimetallic potential-controlled electrolysis is proposed. The electrolytic process of Cu-Ag-Sb alloy is studied by linear scanning voltammetry and electrochemical impedance spectroscopy, and the experimental verification is carried out under the guidance of Cu-Ag-Sb alloy experiments. The results show that gold and silver are enriched in the electrolytic anode slime, while copper and antimony are reduced and deposited on the cathode, which realizes the efficient separation of gold and silver from copper and antimony. The direct yield of precious metals and the anode treatment rate are as high as 99.97 % and 16.02 kg/day·A·m2, respectively, but the energy consumption is 453.90 kW·h/t only. This process strongly supports the treatment of Cu-Ag-Sb-Au alloy with low cost and high efficiency. At the same time, in combination with the vacuum distillation process, the oxidation refining is successfully removed from the lead and copper smelting system, thereby achieving efficient recovery and effective reuse of the precious metals.

Exploring electron-transfer pathways in co-pyrolyzed waste-derived carbocatalyst for enhanced peroxydisulfate activation

Heterogeneous catalyst-activated peroxydisulfate (PDS) process has great potential in environmental remediation, but its complex preparation process, high cost, low efficiency, and unclear mechanism hinder its practical application. To overcome these limitations, we introduced an innovative metal-free biochar catalyst (SCSS-NC) derived from waste biomass through co-pyrolysis of shrimp shell and sludge with nitrogen doping. This catalyst improved its performance, achieving 78.45 % degradation of tetracycline, outperforming sludge carbon/PDS systems (46.89 %) and shell carbon/PDS systems (22 %) under the dosage of PDS (0.5 mM) and catalysts (0.5 g/L) within 60 min. This improvement stems from its increased surface area, porosity, and electron transport capabilities. Quenching experiments, delayed contaminant addition experiments, and EPR results demonstrated that the SCSS-NC/PDS system relies on electron transfer, in which activated PDS binds to the catalyst surface, forming a highly reactive composite [SCSS-NC/PDS]* to degrade pollutants. The open-circuit potential and linear scanning voltammetry results confirm the existence of an electron transfer pathway, while the situ Raman spectroscopy results validate the presence of the composite [SCSS-NC/PDS]*. The DFT theoretical calculations provide further confirmation of the conductivity, low energy barrier, and ability to expedite electron transfer exhibited by SCSS-NC. The catalyst performance and characterization before, after, and post-recovery from the reaction pinpoint key active sites: pore adsorption, sp2 graphitic carbon, and graphitic nitrogen doping sites. The SCSS-NC/PDS system demonstrates robust anti-interference capability, suggesting its potential for practical organic wastewater treatment. This study provides novel insights into economical carbocatalyst and their mechanisms for environmental applications.

Ti-coated diamond micro-powder for the manufacture of the electroplated diamond wire saw

The electroplated diamond wire saw has been widely used in the production of semiconductors, photovoltaic devices, etc. Composite electroplating is an important process in the production of electroplated diamond wire saws. The utilization of nickel (Ni)-coated diamonds is a widely adopted approach to enhance the efficiency of the composite electroplating process employed in the manufacturing of wire saws. However, the pristine diamond does not chemically react with Ni, and the interfacial bonding strength between the Ni coating and the diamond is relatively weak. This frequently results in the detachment of diamonds from the Ni coating during the cutting process. To solve this problem, titanium (Ti)-coated diamonds were used in the preparation of wire saws. We had specially developed a vacuum slow evaporation technology to produce diamond micro-powder (8 μm) with uniform conductive Ti coatings that were firmly bonded with diamond through the interfacial product TiC. A series of electrochemical test results were used to demonstrate the effect of Ti coating on the composite electroplating process. The linear scanning voltammetry curves showed that the addition of Ti-coated diamond shifted the overpotential of composite electroplating in a positive direction, so it promoted the electrodeposition reaction more than diamond powder. The electrochemical impedance spectroscopy revealed that the conductive Ti-coated diamond reduced the charge transfer resistance during composite electroplating. The Ti-coated diamond micro-powder was completely enveloped by an electroplated Ni layer, and TiC formed between the Ti coating and the diamond provided a stronger interfacial bonding force compared to that of the Ni-coated diamond micro-powder. After cutting, the Ti-coated diamond was found not to fall off the wire saw. The use of Ti-coated diamond micro-powder as an abrasive will significantly improve the product quality of mass-produced electroplating diamond wire saws.

Preparation and evaluation of S-rGO/ZnFe2O4/NiCoLDH nanocomposite electrocatalyst in oxygen reduction reaction

This study introduces a novel combination of sulfur-doped reduced graphene oxide (S-rGO), zinc ferrite (ZnFe2O4) and nickel cobalt layered double hydroxide (NiCoLDH) as an efficient and low-cost electrocatalyst for oxygen reduction reaction (ORR) for the first time. The hydrothermal method is used to synthesize all samples including graphene oxide (GO), S-rGO, NiCoLDH, ZnFe2O4 and S-rGO/ZnFe2O4/NiCoLDH hybrids. X-ray diffraction (XRD) analysis, field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM), energy dispersive x-ray analysis (EDX), electrochemical surface area (ECSA), and fourier transform infrared spectroscopy (FTIR) analysis are used to determine the structure of synthesized electrocatalysts, physical properties, and morphology. The electrochemical measurements are carried out using cyclic voltammetry (CV), linear scanning voltammetry (LSV), chronoamperometry (ChA), and electrochemical impedance spectroscopy (EIS). The results for all samples are compared with the Pt/C commercial catalyst. According to the electrochemical results, the S-rGO/ZnFe2O4/NiCoLDH electrocatalyst has the best electrochemical performance. Moreover, the nanocomposite exhibited better electrocatalysis, a high diffusion limiting current density of −5.4 mA cm−2 and an onset potential of 0.03 V. Based on the results of this study, the LDH enhances electrical conductivity, electrocatalytic activity, active surface area, and stability of the catalyst for ORR after combining with carbon bases and ferrite.

Selectivity Study of Anodic Seawater Electrolysis Catalysts Using the Rotating Ring-Disc Electrode Method

Seawater Electrolysis is an exciting alternative to freshwater electrolysis; however, it suffers from a multitude of issues that must be resolved before the technology can be scaled. Corrosive hypochlorite forms at the anode of seawater electrolysis and can damage catalysts and electrolyzer components. Hypochlorite is unstable and can decay, particularly when exposed to heat and metal ions, which can lead to erroneously high oxygen evolution reaction (OER) selectivity conclusions, resulting in poor catalyst and electrolyzer component selection. In this study, we use the rotating ring-disc electrode technique to characterize the selectivity of IrO2, NiO, Co3O4, RuO2, Pt and PtRu electrocatalysts in situ at near-neutral pH (8.4) with linear scan voltammetry (LSV), potentiostatic and galvanostatic experiments. Our findings reveal that elevated temperatures are conducive to higher OER selectivity. Furthermore, when we increased the chloride concentration in the electrolyte with an IrO2 catalyst, we observed that although the overall selectivity towards the OER reaction decreased, the OER current independently increased, indicating a synergistic relationship.

Highly sensitive determination of acyclovir using Ti3C2-CS-MWCNTs-COOH/GCE composite as a sensing platform

Acyclovir (Acyclovir, ACV) is an antiviral drug which, despite its favorable safety profile, can have systemic adverse effects, following improper use. This study prepared a clay-like two-dimensional transition metal carbide Ti3C2 by etching Ti3AlC2 with LiF and HCl. Carboxylated multi walled carbon nanotubes (Carboxylated multi-walled carbon nanotubes, MWCNTs-COOH) were combined with Ti3C2 using chitosan (Chitosan, CS) as solvent and ultrasonic treatment. The nanocomposite was then modified onto the surface of a glassy carbon electrode (Glassy carbon electrode, GCE) to develop an electrochemical sensor for the detection of ACV. The Ti3C2-CS-MWCNTs-COOH/GCE nanocomposite was characterized by X-ray diffractometry (X-ray diffractometry, XRD), scanning electron microscope (Scanning electron microscope，SEM), and cyclic voltammetry (Cyclic voltammetry，CV), as well as the electrochemical impedance method (Electrochemical impedance，EIS). The successful preparation of Ti3C2-CS-MWCNTs-COOH, and the good electrochemical performance of the electrode were verified. Linear scanning voltammetry (Linear scan voltammetry，LSV) was used to quantify the ACV. The linear range of the method is wider than other works (0.05 ∼ 20.0 and 20.0 ∼ 500.0 μM), with a low detection limit (0.088 μM). The sensor achieves sensitive detection of ACV and can be used for the analysis of ACV in pharmaceutical and urine dosage forms, with recoveries of 95.5∼97.6% and 95.6∼97.5%, respectively. For the first time, this sensor utilizes clay-like Ti3C2 with a larger specific surface area in combination with MWCNTs-COOH for ACV detection, which exhibits excellent immunity to interference, repeatability, reproducibility, and stability. This method provides a rapid and sensitive method for the determination of ACV, and lays foundations for developing miniaturized field rapid test detectors.

SnOx embedded into 3D RGO network for enhanced photoconductive performance

In this study, tin dioxide with vacancies (SnOx) was compounded with three-dimensional reduced graphene oxide (3D RGO) to obtain SnOx/3D RGO. The morphology, optical properties and structural composition of SnOx/3D RGO were analyzed by a series of techniques, and the photoconductive properties of the SnOx/3D RGO composites with different mass fractions of RGO were investigated. The photocurrent density of SnOx/3D RGO at 3D RGO mass fraction of 1.5 % reached a maximum value of 2.77 × 10−4 A/cm2, which was about twice and 1.2 times as large as that of SnOx and SnOx/2D RGO (two-dimensional reduced graphene oxide), respectively. In the linear scanning voltammetry and Mott-Schottky analysis results, SnOx/3D RGO exhibited the highest photocurrent (6.34 × 10−3 A/cm2) intensity at 1.0 V bias and the largest carrier density (2.61 × 1021cm−3). This was due to the fact that RGO played a charge transfer role in the composite material in both 2D and 3D structures. In contrast, the porous 3D RGO could connect separate lamellae, which prevented the aggregation of layers and enhanced the electron transfer, thus exhibiting superior performance than 2D graphene.

Production of green hydrogen through PEM water electrolysis

Abstract The need for abundant, sustainable, and clean energy is becoming increasingly important in the modern world due to continuous population growth and industrial expansion. Hydrogen (H2) has been identified as a potential energy carrier due to its high gravimetric energy density. Because H2 is not frequently found in its molecular form, it has to be obtained through various methods such as steam methane reforming, coal gasification, fossil fuels, and electrochemical techniques. H2 produced via PEMWE has proved to be an efficient method compared to other electrolysers. The limiting factor of a PEM electrolyser system is the OER catalyst. Commercially, IrO2 and RuO2 are used; however, both these metals are rare and expensive. Current research reports the use of binary metal oxides as an alternative OER catalyst to decrease the overall CAPEX costs. Various synthesis methods are available, with the Adams’ fusion method being the simplest. Characterisation techniques used to evaluate the performance of these catalysts include cyclic voltammetry (CV), linear scan voltammetry (LSV), XRD, XRF, SEM/EDS, and chronopotentiometry. Hydrogen as a clean fuel has a broad potential for use across all sectors, including transportation, residential, and industrial. In recent years, extensive research has been done on all aspects of hydrogen production, storage, and transportation. This review paper aims to study other bimetallic metals to reduce the Ir content used as an oxidative evolution reaction to reduce the capital cost of the PEM electrolyser. To produce green hydrogen that could reduce the carbon footprint in several industrial processes.

Electrochemical Assay of Mammalian Cell Viability

We present the first use of amperometric detection to assess the viability of mammalian cells in continuous mode, directly in the cell culture medium. Vero or HeLa cells were injected into electrochemical sensors equipped with a 3-electrode system and containing DCIP 50 µM used as the redox mediator. DCIP was reduced by the viable cells and the reduced form was detected amperometrically at 300 mV vs silver pseudo-reference. The continuous regeneration of the oxidized form of the mediator ensured a stable redox state of the cell environment, allowing the cells to survive during the measurement time. The electrochemical response was related to cell metabolism (no response with dead cells or lysed cells) and depended on both mediator concentration and cell density. The protocol was applied to both cells in suspension and adhered cells. It was also adapted to detect trans-plasma membrane electron transfer (tPMET) by replacing DCIP by ferricyanide 500 µM and using linear scan voltammetry (2 mV/s). The pioneering results described here pave the way to the development of routine electrochemical assays for cell viability and for designing a cell-based analytical platform.