Surface Morphology Of Electrode Research Articles

Influence of Bi3+ Doping on Electrochemical Properties of Ti/Sb-SnO2/PbO2 Electrode for Zinc Electrowinning.

Bi3+ doped Ti/Sb-SnO2/PbO2 electrode materials were fabricated by electrodeposition to improve their electrochemical performance in zinc electrowinning. The surface morphology, chemical composition, and hydrophilicity of the as-prepared electrodes were characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and contact angle. An electrochemical measurement and an accelerated lifetime experiment were also conducted to investigate the electrocatalytic performance and stability of the electrodes. The results show that the Bi3+ modification electrode has an important effect on the coating morphology, the crystal structure, the surface hydrophilicity, the electrocatalytic activity, and the stability. The electrode prepared from the solution containing 2 mmol·L-1 Bi(NO3)3 (marked as the Ti/Sb-SnO2/2Bi-PbO2 electrode) exhibits the best hydrophilicity performance (θ = 21.6°) and the longest service life (1196 h). During the electrochemical characterization analysis, the Ti/Sb-SnO2/2Bi-PbO2 electrode showed the highest oxygen evolution activity, which can be attributed to it having the highest electroactive surface (qT* = 21.20 C·cm-2) and the best charge-transfer efficiency. The DFT calculation demonstrated that the doping of Bi3+ leads to a decrease in the OER reaction barrier and an increase in the DOS of the electrode, which further enhances the catalytic activity and the conductivity of the electrode. Moreover, the simulated zinc electrowinning experiment demonstrated that the Ti/Sb-SnO2/2Bi-PbO2 electrode consumes less energy than other electrodes. Therefore, it is expected that the Bi3+ modified electrode will become a very promising electrode material for zinc electrowinning in the future.

Balancing current density and electrolyte flow for improved zinc-air battery cyclability

Zinc-air batteries (ZABs), known for their high energy density and environmental friendliness, are emerging as promising solutions for sustainable energy storage. However, the irregular deposition of zinc on electrodes hinders the widespread utilization of rechargeable ZABs due to limited durability and stability. This study investigates the role of electrolyte flow in enhancing zinc electrodeposition and overall performance in zinc-air flow batteries (ZAFBs) at high current densities. We explore the interplay between current density, flow rate, and their influence on electrode surface morphology and the removal of the passivating zinc oxide layer to improve battery efficiency and lifespan. Using advanced in-situ synchrotron radiation x-ray tomography, we found that incorporating flowing electrolyte at specific current densities results in rounded dendrite tips, thinner and more uniform deposition layers, and improved zinc adhesion. Imaging and electrochemical analyses further reveal that flowing electrolyte enhances zinc morphology, reduces charge transfer resistance, diminishes passivation, and lowers galvanostatic charge/discharge polarization across various current densities, thereby improving battery cycling performance. Notably, the impact of flowing electrolyte is more pronounced at a moderate current density of 50 mA/cm2 compared to lower or higher currents. Our findings underscore the importance of electrolyte flow and current density management in developing high-performance ZAFBs, providing valuable insights for their future commercialization.

Nitrate reduction on bimetallic (Pd0.09Sn0.91) electrodes: Effects of calcination temperature, electrode support, and quenching

The effects of fabrication process, namely, calcination temperature, electrode support, and quenching, on electrochemical nitrate reduction were investigated, exemplified by Pd0.09Sn0.91 electrode. The electrode was characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, and cyclic voltammetry. Results showed that electrode surface morphology, crystalline formation, and chemical composition, which were influenced by the electrode fabrication process, controlled nitrogen selectivity and nitrate reduction reactivity. The Pd0.09Sn0.91/SS electrodes were calcined at different temperatures (from 100 to 700 °C) for 3 h in air and the results showed that high calcination temperature rendered electrode oxidized, and decreased nitrogen selectivity and nitrate reduction capability. Electrode supports affected nitrate reduction following the order of Ni ≈SS > G > Ti. Quenching electrode in ice water decreased nitrate reduction capability. Porous surface with small oxygen content, less degree of metal oxidation (i.e., higher fraction of Pd0 and Sn0), and Sn crystals favored nitrogen selectivity and nitrate removal.

Mechanism of overscreening breakdown by molecular-scale electrode surface morphology in asymmetric ionic liquids

The interfacial nature of the electric double layer (EDL) assumes that electrode surface morphology significantly impacts the EDL properties. Since molecular-scale roughness modifies the structure of EDL, it is expected to disturb the overscreening effect and alter differential capacitance (DC). In this paper, we present a model that describes EDL near atomically rough electrodes with account for short-range electrostatic correlations. We provide numerical and analytical solutions for the analysis of conditions for the overscreening breakdown and DC shift estimation. Our findings reveal that electrode surface structure leads to DC decrease and can both break or enhance overscreening depending on the relation of surface roughness to electrostatic correlation length and ion size asymmetry.

Exoelectrogenic behaviors of Shewanella oneidensis MR-1 and cytochrome knock-out mutants on smooth electrodes of different materials

The development of anodes supporting a high rate of current generation stands as a crucial and challenging aspect in microbial electrochemical systems. A well-defined electrode surface morphology is essential for comprehending the impact of material intrinsic properties on microbial current generation, offering molecular insights into the respiration of exoelectrogens with electrodes made of diverse materials. We fabricated smooth electrodes (root mean square roughness below 10 nm) using four materials, each representing a distinct class of materials commonly utilized to construct bioanodes. These electrodes were employed to investigate current generation, electrochemical characteristics, and biofilm formation by Shewanella oneidensis MR-1 and mutants lacking cytochromes MtrC (ΔmtrC), MtrA (ΔmtrA), or CymA (ΔcymA). In reactors inoculated with MR-1, the poly(3,4-ethylenedioxythiophene) polystyrene sulfonate electrodes demonstrated a current density of 12.5 ± 1.1 μA cm-2, surpassing the 3.57 ± 0.50 μA cm-2 observed with indium tin oxide electrodes, while current generation levels by gold and glassy carbon electrodes fell in between. This disparity was not attributed to distinct biofilm formations by MR-1, as it formed stable monolayer biofilms on all types of working electrodes. At least five electron transfer pathways were identified in the MR-1 Vammograms, with the activities of these pathways depending on the electrode materials. The effectiveness of both endogenous and exogenous electron mediators varied with the electrode materials involved. Additionally, a phenazine compound exhibited diverse formal potentials when interacting with the biofilm and different types of electrodes. The mutants displayed varying degrees of impaired current generation and biofilm formation capabilities, with ΔmtrA and ΔcymA being the most affected regardless of the electrode used. However, for a specific mutant, the overall current generation, relative contribution by individual pathways, and biofilm formations underwent significant changes based on the electrode materials employed.

Electrodeposition of NiCo on stainless steel substrate using deep eutectic solvent for efficient hydrogen evolution and methanol oxidation reactions

The electrodeposition of NiCo on a stainless-steel substrate using Deep eutectic solvent (DES) was carried out using constant current methods. A 1:2 mol ratio of ChCl (Choline chloride) and crystalline urea was used to prepare DES. The XRD analysis of the fabricated NiCo@SS showed a highly crystalline nature, and the SEM image revealed the fabricated electrode surface morphology. The composition and oxidation state of the deposited material were confirmed by EDAX and XPS techniques. The prepared electrodes were subjected to LSV and CV studies with 1 M KOH using a three-electrode system to analyse its catalytic ability in the Hydrogen evolution reaction (HER) and methanol oxidation reaction (MOR). Among all the deposited electrocatalysts, NiCo@SS demonstrated the highest catalytic activity and excellent stability for the hydrogen evolution reaction (HER), achieving an overpotential of 257 mV at a current density of 100 mA/cm2. Additionally, NiCo@SS exhibited a remarkable current density of 240 mA at a potential of 0.8 V towards the MOR. The synthesized NiCo@SS possessed excellent low overpotential, low charge transfer resistance, high current density, and large surface area. The explored catalyst of NiCo@SS was examined with different concentrations of methanol using the CV technique. Finally, the stability of NiCo@SS, as examined by chronoamperometry and LSV with 3000 cycles, revealed it to be a robust, stable catalyst towards HER and OER.

Highly transparent and conductive Ga-doped InWO multi-component electrodes for Perovskite photovoltaics

Wide-bandgap Ga-doped InWO (GIWO) transparent conductive electrodes (TCE) were fabricated by co-sputtering IWO and Ga2O3, followed by rapid thermal annealing (RTA), with the effects of the Ga dopant content on the electrical, optical, structural, and morphological properties of the GIWO multi-component electrodes investigated to optimize the GIWO electrode. According to the figure of merit (FOM), the GIWO film with a Ga content of 2.1 at% exhibited a low sheet resistance of 9.9 Ohm/square and high transmittance of 91.71 % at a wavelength of 550 nm. The presence of a high Lewis acid strength (LAS) dopant of Ga (1.16) and W (3.15) led to an increase in the carrier mobility of GIWO and transmittance in the near infrared wavelength region. In addition, the strongly preferred (222) and (400) orientations of the GIWO grains increase the carrier mobility and improve the surface morphology of the GIWO electrodes. The successful operation and superior performance of the planar p-i-n structured perovskite solar cells (PSC) fabricated on GIWO electrodes indicate the feasibility of GIWO as a substitute for conventional Sn-doped In2O3 electrodes. The highest-performing PSC with GIWO electrodes exhibited reliable hysteresis with an efficiency difference of less than 1 % depending on the scan direction under standard AM1.5 G conditions.

Nickel Disulfide (NiS2): A Sustainable Low‐Cost Electrode Material for High‐Performance Supercapacitors

In the family of transition metal sulfides, nickel disulfide (NiS2) received significant attention in the recent past, particularly as an electrode‐active material for supercapacitors due to its high specific capacitance, high power density, long cyclic stability, and low cost. A detailed overview on the supercapacitor applications of NiS2 is lacking in the literature. In this review article, the unique features of NiS2 in terms of its various methods of synthesis, characterizations, and electrochemical performance evaluations are described. This review provides an in‐depth understanding on the unique properties of ultrathin nanostructured NiS2 such as structural properties, electronic properties, optical properties, and so on. Later, the various methods of synthesis including hydrothermal method, solvothermal method, solvent‐free approach, and so on are reviewed. Further, the strategies are discussed to improve the electrochemical performance of NiS2 by preparing hybrids or nanocomposites with other types of electrode‐active materials. The influence of electrode nanostructure and surface morphology on the charge storage is discussed with the help of specific examples. Furthermore, the potential challenges and future perspectives of NiS2 for commercial supercapacitors are examined. This review proclaims the development of novel approaches and strategies for the effective utilization of NiS2‐based electrodes for high‐performance low‐cost supercapacitors.

Enhanced Supercapacitive Performance in Catalyst‐Free Binary Composite SnO2–RuO2 Nanostructured Thin Films for Symmetric Supercapacitor Device

In the present work, thin film electrodes of ruthenium oxide (RuO2), tin oxide (SnO2), and their composite SnO2–RuO2 are deposited on 304 stainless steel substrates using pulsed laser deposition (PLD). These nanostructured electrodes are then evaluated for their suitability in electrochemical energy storage applications. A symmetric supercapacitor device (SSD) is constructed using the SnO2–RuO2 composite electrodes. Compared to individual SnO2 and RuO2 electrodes, the composite electrodes exhibit enhanced specific capacitance and cycle life. This improvement is attributed to modifications in surface morphology and electronic properties. This modified surface morphology of the composite electrode, creates favourable conditions for electrolyte interaction and ion transport, ultimately contributing to the observed increase in specific capacitance. Specifically, the composite electrode demonstrates a specific capacitance of 170.2 Fg−1 at a current density of 0.1 mA cm−2, outperforming SnO2 (37.4 Fg−1). The SnO2–RuO2//SnO2–RuO2 SSD exhibites a specific capacitance of 70.0 Fg−1 at a current density of 0.1 mA cm−2, coupled with energy density and power density values of 19.05 Wh kg−1 and 645 W kg−1, respectively, within a voltage window of 1.4 V. The SSD displays an impressive capacitive retention of 81.27% over 10 000 cycles, indicating its potential for practical energy storage applications.

Functionalization of Carbon Electrode Surface Using Polyaniline and Gold Nanoparticles for Protein Immobilization

This study presents a screen-printed carbon electrode surface functionalization to immobilize proteins. The process involves the deposition of gold nanoparticles on the carbon electrode and subsequent surface modification to immobilize bovine serum albumin–fluorescein isothiocyanate conjugate (BSA-FITC). A combination of conducting polymer and gold nanoparticles was employed to enhance the electrode contact area and current transmission. The electrode surface morphology and properties were evaluated by scanning electron microscopy (SEM) and Raman spectroscopy, showing the porous polyaniline (PANI) film has been formed on the carbon electrode surface with the network of dendritic nanofibers. Gold nanoparticles were evenly distributed on the PANI film to form a nanocomposite material layer on the carbon electrode. The observed size of these gold nanoparticles was significantly smaller than those on the electrode without a PANI film. Additionally, the current transmission of this composite material layer has been verified by cyclic voltammetry (CV). The results show that the amplitude of the redox peak was doubled compared to the bare carbon electrode and gold nanoparticle-only deposited electrode. Moreover, the success of the process was verified by fluorescence and cyclic voltammetry. The fluorescent green color observed under the microscope indicated that BSA-FITC was on the electrode surface. The change of CV signal after each step verified the formation of a new layer on the electrode surface. These results are anticipated to play an important role in developing high-sensitivity immunosensors in the future.

Efficient chlorine evolution of CuO modified RuO2 electrode and its application in preparation of electrochemical disinfectant

Electrochemical chlorine evolution reaction (CER) is one of the most important practical applications of electrochemical reaction, which can be used for electrochemical disinfection. The electrochemical disinfectant of acidic electrolyzed water (AEW) is obtained by electrolyzing extremely dilute chlorine-containing solution in ion-exchange membrane electrolyzer. In the anode area, HClO is produced by CER, which has a strong bactericidal effect. Due to the low concentration of chloride ion, it is necessary to improve the CER selectivity of the electrode in order to improve the efficiency of chlorine electrolysis. In this paper, CuO/RuO2 electrode was prepared by the two-step thermal decomposition method, and the surface morphology and electronic structure of RuO2 electrode were modified. Compared with the ordinary RuO2 electrode, the CER activity of CuO/RuO2 electrode is improved. For the oxygen evolution reaction (OER), the activity of CuO/RuO2 electrode is significantly lower than that of RuO2 electrode. The CER mechanism of CuO/RuO2 electrode is the second electron transfer, and the OER mechanism is the formation and transformation of OHads. The potential difference between CER and OER of CuO/RuO2-3 electrode is 105 mV, which is 52 mV higher than that of RuO2 electrode, so the selectivity of CER of CuO/RuO2 electrode is remarkably improved. During the preparation of AEW, the HClO of AEW2 (prepared by CuO/RuO2-3 electrode) is 0.72 mmol/L, which is 2.5 times that of AEW1 (prepared by RuO2 electrode). In the sterilization experiments on E. coli and B. subtilis, the germicidal efficacy of AEW2 (3.71 and 2.99 log10 CFU/mL) is obviously superior to that of AEW1 (0.76 and 0.61 log10 CFU/mL).

Effect of atomization amounts on electrical discharge ablation machining and electrochemical machining

ABSTRACT This study investigated the impact of varying atomization amounts on composite machining involving both atomized electrical discharge ablation machining and electrochemical machining (EDAM-ECM). Additionally, this study examined the effects of different atomization amounts on the material removal rate, relative electrode wear rate, processing waveforms, surface roughness, surface morphology and elements, and the EDAM-to-ECM ratio. Moreover, a theoretical model for describing the material removal process in composite processing was developed. Furthermore, the effect of the ECM ratio on the processing results was quantitatively analyzed through the integration of statistical circuits with a formula for calculating recast layer thickness. The model was used to predict and select the optimal atomization amounts required to achieve recast layer removal during processing. The results revealed that at an atomization amount of 200 mL/min, 16.7% of the total material removal was attributable to ECM, indicating the successful removal of the recast layer. At this atomization amount, the fabricated sample maintained a machining precision of 0.02 mm.

Synthesis of nanoporous solid polymer electrolyte AuNiCe/NC hydrogenation membrane electrode

In this study, using graphite fiber cloth as the support, gold-based solid polymer electrolyte (SPE) membrane electrodes were synthesized by high-vacuum ion beam sputtering, nitrogen doping of the support, combined electrochemical dealloying, and hot-pressing technology. The application of the SPE membrane electrode to couple hydrogen evolution and liquid organic hydrogen storage is of significant importance for sustainable hydrogen energy and efficient carbon dioxide conversion. Using various characterization techniques, we systematically analyzed the phase structure, surface morphology, porous structure, and electrocatalytic performance of the membrane electrode for the hydrogenation of cyclohexene. The results indicated that doping the carbonaceous support with nitrogen (NC), doping with cerium as catalyst promoter, and combined electrochemical dealloying can all enhance the activity of the catalyst. Cerium doping provides the catalyst with oxygen vacancies for accelerated electron transfer. After combined electrochemical dealloying, AuNiCe/NC formed a three-dimensional bicontinuous porous structure. The electrochemically active surface area increased by 23.94 times, the energy consumption of catalytic cyclohexene hydrogenation decreased by 35.7%, and current efficiency and the formation rate of cyclohexane increased by 54.9% and 29.4%, respectively.

Arcing Stabilization Effect and Ablation Characteristics for C–Cu Electrodes at Low Air Pressure

Arc ablation is a widespread problem in electrical contact systems. The fault of the system caused by arc ablation significantly restricts its lifespan. Facing the development goal of electrified aircraft and low vacuum high-speed railways, the problem of arc ablation at low air pressure cannot be ignored. In this paper, an experimental platform for arcing and ablation at low air pressure is built. The influence of low air pressure on the characteristics of arc ablation is explored. The results show that the stability of the arc column at low air pressure varies significantly. Under the condition of different air pressures, the traces and morphology in the ablation region of the electrode differ significantly. These are caused by Rayleigh-Taylor instability between the arc and air, and by the motion of the arc root which is driven by the arc column. Importantly, the low-pressure stabilization effect for the arc is found. The corresponding relationship between electrode ablation traces, surface morphology, and air pressure is revealed. The action mechanism of air pressure on the arcing process and ablation characteristics of the electrode are clarified. This research provides theoretical support for restraining arc ablation and prolonging the lifespan of the electrical contact system.

A novel and efficient voltammetric sensor for the simultaneous determination of alizarin red S and tartrazine by using poly(leucine) functionalized carbon paste electrode

In the current work, a rapid, selective, and sensitive technique was developed for the detection of Alizarin Red S (ARS) by applying poly leucine modified carbon paste electrode (PLMCPE). Electrochemical impedance spectroscopy (EIS) and Scanning electron microscopy (SEM) were utilized to study the surface morphology of unmodified carbon paste electrode (UMCPE) and PLMCPE. The active surface area for UMCPE and PLMCPE was found to be 0.0012 cm2 and 0.0026 cm2 respectively. The electrochemical response of ARS at UMCPE and PLMCPE was analyzed using cyclic voltammetry (CV) in the potential window of 0.4 to 1.0 V. The cyclic voltammogram obtained for varying the pH of 0.2 M phosphate buffer (PB) solution showed maximum current for the oxidation of ARS at pH 6.5. The electrochemical reaction of ARS was found to be irreversible and adsorption controlled. The effect of variation of concentration of ARS on the oxidation peak current was evaluated using CV and linear scan voltammetry (LSV). A linear relationship between the concentration variation and current was obtained in the linear range of 1.5 μM–3.5 μM and 0.2 μM–5.0 μM for CV and LSV respectively. The limit of detection (LOD) of 0.68 μM for the CV method and 0.29 μM for the LSV method was exhibited by the developed sensor. The simultaneous study of ARS along with tartrazine (TZ) showed good selectivity for ARS. The interferents of foreign molecules showed no effect on the selectivity of the electrode. The applicability of PLMCPE on real samples gave good recovery ranging from 97.46–101.2%; hence, the sensor can be utilized on real samples. The developed sensor has good stability and sensitivity.

Fast and precise CoFe3O4/TiO2/MWCNT-based voltammetric sensor preparation for salbutamol determination

Salbutamol is an important drug that opens the medium and large air spaces in the lungs. In this study, CoFe3O4, CoFe3O4/MWCNT, and CoFe3O4/TiO2/MWCNT modified electrode structures are prepared separately to determine the effect of each modification agent on salbutamol responses. The prepared electrodes are firstly structurally characterized by the FT-IR technique. The surface morphology and structure of electrodes are then analyzed by SEM, and AFM techniques. EDX analyses were performed to clarify this structural change on the electrode surface. The salbutamol activity of the modified electrodes is determined by DPV in 0.1 M PBS. The modified electrode shows a linear response in the concentration range of 2-18 µM salbutamol, and an R2 value of 0.9587 is achieved. LOD and LOQ of the modified electrode are determined as 1.39 µM and 22.87 µM, respectively. Considering the reproducibility of the experimental results, non-interference of the interfering species, and the measurement range, it is determined that it can be successfully used to figure out the concentration of salbutamol in physiological fluids and commercial form.

A Review of Development of Chemical Sensors

A comprehensive summary of the most recentre search concentrating on chemical sensors utilizing nano tubes,Nano rods,Nano belts, and nano wiresis given in this article. The experimental principle, sensor device design,sensor mechanism, and multiple significant conclusionsreceivethevastmajorityofourattention.Thefollowingfoursectionsprovide additional information on the creation of chemical sensors based on nanostructured materials: nanotube sensors, Nano rod sensors, Nano belt sensors and Nano wire sensors. Weconcludethisreviewwithpersonalperspectivesonthedirectionstowardswhichfuture research on nanostructured sensors might be directed. At ambient temperature, the nanotube sensors show a far faster response time and a significantly higher sensitivity than the current solid-state sensors. Reversibility of the sensor can be obtained by heating it to a high temperature or by slowly recovering under ambient conditions. Over the past decade, synthesized nanomaterial’s, such as carbon nanotube, nanoparticle, quantum dot, and nanowire, have already made breakthroughs in various fields, including biomedical sensors. Enormous surface area-to-volume ratio of the Nano materials increases sensitivity dramatically compared with macro-sized material. Herein we present a comprehensive review about the working principle and fabrication process of nanowire sensors. Then anotube sensor sex hibit a fast response and asubstantially higher sensitivity than thatofexistingsolid-statesensorsatroomtemperature.Sensorreversibilityisachievedbyslow recovery under ambient conditions or by heating to high temperatures.Synthesized Nano materials, including carbon nanotubes, nanoparticles, quantum dots, and nanowires, have already achieved significant advances in a number of sectors, including biological sensors, during the last ten years. When compared to macro-sized material, the nanoparticles' enormous surface area-to-volume ratio significantly boosts sensitivity. We provide a thorough overview of the fabrication process and operating principle of the nanowire sensor here. Recent advances including self-powering, reusability, sensitivity in high ionic strength solvent,andlong-term stabilityaresurveyedandhighlightedas well.Nanowire isexpectedtolead significant improvement of biomedical sensor in the near future.Advantages and disadvantages of the sensors are provided along with brief descriptions. An electrical device that monitors changes in a quantity, such as voltage, temperature, pressure, or humidity, is called a sensor. As a result, classification is done according to the attribute that a sensor measures. A temperature sensor detects even the smallest variations in its environment or shifts in temperature, such as hot or cold weather. Microelectronic manufacturing techniques have been used to manufacture chemical and electrochemical sensors.Thedevelopment ofchemical sensors has been spurred forward by the recentadvancesinmicromachingtechnology.Chemicalsensorresearchhasadvancedthanksto micro machining methods like sacrificiallayers, plasmaetching, andchemicalanisotropicetching. These methods enable the creation of low mass, low power driven devices as well as controlled working conditions and temperature. Researchersbecameinterestedinthesecarefullychoseninvitronanostructureswhentheywere combined with nanomaterials because the improved properties of these nanostructures led to advances inthe analytical performance of chemical and biosensors. Thisstudycoversthe latest advancements in recognition elements that are integrated in to chemical sensors and bio sensors used in the food, medical, and environmental domains. These elements include both traditional ones like enzymes and antibodies as well as more modern ones like aptomers and phages.Cyclic voltammetry and electron microscopy are frequently used in the characterization of chemically modified sensors and biosensors because they enable the confirmation of electrode mechanisms and surface morphologies. X-ray photoelectron spectroscopy (XPS), among other methods, is a special tool for obtaining information on the sensor surface that is qualitative, quantitative/semi-quantitative, and speciation-related. However, XPS is still not widely applied in this industry. The purpose of this work is to review a few selected studies that demonstrate how wellXPSperformswhencharacterizingthetopsurfacelayersofbiosensorsandchemically Modified sensors. The reader is provided with the necessary background information in a brief introduction to X-ray photoelectron spectroscopy. The use of XPS to characterize sensors appropriate for environmental and food analysis is highlighted.

Microstructure of Pure Magnesium and AZ31 Magnesium Alloy Anodes after Discharge/Charge Cycles for Rechargeable Magnesium Batteries

This study investigated the microstructure of pure magnesium (Mg) and AZ31 (Al—3 wt%; Zn—1 wt%) Mg alloy anodes after different discharge/charge cycles in an all phenyl complex (APC) electrolyte for rechargeable Mg batteries. When discharging the as-immersed Mg metal electrodes, the stripping morphologies of pure Mg and AZ31 Mg alloy electrodes are inhomogeneous with numerous discharge holes. In the subsequent charge stage, the plated Mg preferentially deposits along the circumferences of the discharge holes, which could be related to the distribution of Mg and Cl complex ions near the electrode surface after discharge. Later discharge/charge cycles on pure Mg show that both the plated Mg and the pure Mg substrate are stripped during discharge, resulting in an incomplete stripping of the plated Mg and a non-uniform electrode surface morphology after cycles. In contrast, AZ31 Mg alloy shows a higher stripping resistance than pure Mg, so the plated Mg is preferentially stripped during discharge. Near complete stripping of the plated Mg on AZ31 Mg alloy electrode results in a more uniform electrode surface morphology after cycles and a mitigated increase in the difference between the discharge and charge potentials.

Construction of a binder-free PANI-CQD-Cu electrode via an electrochemical method for flexible supercapacitor applications.

In recent years, flexible hybrid supercapacitors (FSCs) have played a significant role in energy storage applications owing to their superior flexibility and electrochemical properties. In this study, carbon quantum dots (CQDs) were prepared from ascorbic acid via a hydrothermal method and physical and chemical characterizations were performed. Then, the carbon quantum dots (CQDs) were doped with polyaniline (PANI) and copper (Cu) to form a PANI-CQD-Cu composite coated on carbon cloth (CC) using an electropolymerization method. In the polymerization process, CQDs bind with the PANI chain and form a PANI-CQD-Cu composite. The prepared electrode's functional group and surface morphology were characterized through XRD, Raman, BET, XPS and SEM with EDAX studies. The electrochemical properties of the PANI-CQD-Cu electrode were investigated using cyclic voltammetry, impedance spectroscopy and galvanostatic charge-discharge study. The capacitance value of PANI-CQD-Cu was 1070 mF cm-2 at 5 mA cm-2 (1070 F g-1 at 1 A g-1), which was higher than that of PANI (775 mF cm-2). Moreover, a flexible asymmetric supercapacitor (FASC) based on an activated carbon/PVA-H2SO4/PANI-CQD-Cu device was fabricated, which exhibited outstanding energy and power densities of 23.10 μW h cm-2 and 0.978 mW cm-2, respectively. The capacitance value remained at 92% after 3000 cycles. The outcome results indicated that the PANI-CQD-Cu-coated CC electrode material can be a promising electrode material for practical energy storage applications.

Fabrication of efficient and economical dye-sensitized solar cells using carbon-coated nanotextured silicon wafers counter electrodes

Significant progress has been made in various fields of photovoltaics in response to the growing demand for alternative energy resources. Silicon technologies dominate the current solar cell market, but carbon-based photovoltaics are known for their ability to be produced at low cost and in large quantities. The electrocatalyst accelerates the conversion of tri-iodide into iodide ions at the interface between the counter electrode and the electrolyte, according to DSSC principle. During the catalytic process, the accessible sites for the reaction between the reactants and the catalyst are greatly influenced by the surface area and morphology of the counter electrode and electrocatalyst. Therefore, in this work, silicon micro cubes with different patterns were fabricated using lithography, and a carbon layer has been coated directly using chemical vapor deposition on the surface of silicon samples with 15, 30, and 60 mins growth times. The functionalized silicon surface with the carbon layer subsequently demonstrated electrocatalytic activities for iodide/triiodide reduction. In DSSCs, the carbon-coated samples have been utilized as counter electrodes. The samples were characterized using Raman spectroscopy and scanning electron microscopy. DSSCs were fabricated for each synthesized counter electrode, and DSSCs performance has been analyzed for each DSSC. Utilizing carbon-coated nanotextured silicon wafers as the counter electrodes, DSSCs were able to achieve the maximum power conversion efficiency of 6.73%. The current results pave the way toward the replacement of expensive Pt-based conventional DSSCs.