Papers by Keyword: Cyclic Voltammetry

Abstract: This study investigates the corrosion resistance of Stainless Steel 201 through varying surface treatments and testing in a 3.5 wt% NaCl solution, mimicking seawater conditions. Given its prevalent use in industries like oil, Stainless Steel 201's resistance to pitting corrosion is crucial, primarily when used in pipes. The research employs electrochemical techniques, specifically Cyclic Voltammetry and Immersion, to treat the material's surface. The surface treatment using citrict acid (C₆H₈O₇) varying the concentration of 1, 1.5, and 2 M. Corrosion tests utilize open circuit potential, anodic polarization patterns, and characterization via optical microscopy and SEM-EDS. Results indicate that the material subjected to a Cyclic Voltammetry treatment with 2M citric acid exhibited the lowest corrosion rate at 0.001243 mmpy, with 21 instances of pitting corrosion. Conversely, untreated Stainless Steel 201 showed a higher corrosion rate of 0.006177 mmpy and 87 instances of pitting corrosion. This underscores the significant improvement in corrosion resistance achieved through the specified surface treatment, highlighting its potential value for enhancing Stainless Steel 201's longevity and performance in corrosive environments. Keywords: Stainless Steel 201, Cyclic Voltammetry, Immersion, Open Circuit Potential (OCP), Anodic polarization Patterns, Corrosion Rate, Pitting Corrosion.

Abstract: It has been demonstrated that thin films of fluorine-doped Bi₂O₃ can be prepared using sol-gel spin coating. An X-ray diffraction (XRD) and energy dispersive analysis were used to examine samples. Using a sol-gel spin-coating technique, different electrolytes and sweep rates were used in the study to characterize fluorine-doped Bi₂O₃ films. In the results of the studies, it was extensively examined whether these films could be used in the fabrication of electrochromic devices. The enhanced properties of fluorine doped samples are due to their increased separation efficiency and strong oxidation potential. For two hours, the samples were exposed to temperatures ranging from 350 °C to 450 °C. F:Bi₂O₃ films have been the subject of an intercalation and deintercalation investigation. Therefore, H₂SO₄ and KCl are used to intercalate H+ and K+ ions in PC electrolytes. Sharp transmittance peaks at the band's edge in a spectrum with good crystallinity signify interfering patterns. Band assignment 3482 cm^-1, stretching vibration of carbohydrate, C-OH, 2432 cm^-1 asymmetric stretching vibration, 1625 cm^-1 unconjugated C=O stretching vibration, and 1383 cm^-1 bending vibration of C-H are among the numerous assignments in Fourier transform infrared spectroscopy. Additionally, 1101 cm^-1 are vibrations of hydroxyl groups and 625 cm^-1 are metallic bond vibrations of F:Bi₂O₃. The surface roughness of F:Bi₂O₃ films was found to have significantly improved. It is probable that a sol-gel spin coating process at 200 °C produced dense, irregularly shaped Bi₂O₃ grains. The thermodynamic characteristics of the corrosion process for Bi in concentrated sulfuric acid solution were studied. These parameters were Ea (activation energy), H (enthalpy change), and S (entropy change).

Abstract: This study investigates the electrochemical reduction of quinine (QN) detection using boron-doped diamond electrodes (BDD). Different pulse voltammetry (DPV) of QN in a 0.1 M PB solution exhibits reduction peaks at -0.86 V (vs. Ag/AgCl). Additionally, the effects of pH and scan rate were explored to investigate the reduction mechanism within a potential range of -1.4 V to -0.4 V (vs. Ag/AgCl). Furthermore, a linear calibration curve was observed in the concentration range of 2 μM to 25 μM (R²=0.99) with a detection limit of 0.62 μM (S/B=3).

Abstract: Battery-supercapacitor hybrids (BSHs) are promising energy storage devices that exhibit large energy density, high power density. In this research, BSH devices based on Li₄Ti₅O₁₂ and Ti₃C₂ electrodes are fabricated. Through cyclic voltammetry, it is discovered that the kinetics of charging/discharging are diffusion-controlled. 3D Bode plots and Nyquist Plots indicate that bounded diffusion might occur. Regarding the performance, the 70 wt.% Li₄Ti₅O₁₂-Ti₃C₂ BSH shows the most balanced specific energy (9.9 mW∙h/kg) and specific power (3.0 W/kg) at 100 mV/s. The largest specific capacitance of the 70 wt.% Li₄Ti₅O₁₂-Ti₃C₂ BSH is 81.6 F/kg at 5 mV/s.

Abstract: Mesoporous silica nanoparticles were synthesized via sol–gel method to produce uniform size nanoparticles using n-Octadecyl-trimethoxy silane which gives a good dispersion of silica nanoparticles in hydrophobic mediums. Scanning electron microscopy (SEM), infrared spectroscopy, X-ray diffraction (XRD), thermal gravimetric analysis, and nitrogen adsorption-desorption tests were used to thoroughly investigate the nanocomposites' morphology and structure. BET results show a high surface are of 760 m²/g and specific high pore size (30Ȧ) and pore volume (0.336 cm³/g). The SEM results present that the mesoporous silica nanoparticles possess a well dispersed and uniform particle morphology and FTIR interpenetrating the well-prepared silica nanoparticles which possess Si-O-Si and Si-O bond. The XRD analysis confirmed the amorphous nature silica nanoparticles. The electrochemical properties of silica nanoparticles were evaluated in a potassium chloride solution. With the advantages of a large specific surface area and a suitable pore size distribution, a pair of broad and symmetric redox peaks centred at -0.15 V and 0.6 V appears. Mesoporous silica with a large effective specific surface area demonstrated excellent electrochemical performance, making them excellent candidates for supercapacitors and fuel cells.

Abstract: In the present research work, carbon nanosphere (5 wt. %, 10 wt. % and 15 wt. %)/Zr- based metal organic frame works (CNS: Zr (II)-MOFs) with different molar ratios of the legend 4-{[(1E)-1-Hydroxy-3-Oxoprop-1-En-2-yl] Sulfanyl} Benzoic Acid (HOSBA) have been successfully synthesized by hydrothermal method. Studies using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA) have validated certain structural, optical, and morphological features. The supercapacitance performance of the synthesized MOFs was investigated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). At a current density of 0.5 A g^-1 and at a scan rate of 10 mV/s, the 15% CNS doped Zr-MOF demonstrated highest specific capacitance (C_s) of 239.4 F g^-1. 15 wt.% CNS doped Zr-MOF proven power density of 2100 W kg^-1 and maximum energy density of 14.82 Wh Kg^-1 with capacitive retention of 77.63 % following 2000 cycles mark this combination a good for supercapacitors (SCs) material. Regardless of the synthetic conditions, we achieved MOFs which exhibited hetero structure formation with spherical morphologies. The results open us new and energy approach for the supercapacitor of the Zr-metal based MOFs and applications in the photonics, optoelectronics, and promising electrode material for electrochemical energy storage systems.

Abstract: The addition of zinc oxide (ZnO) as impregnation for activated carbon (AC) with the hydrothermal method has been performed in this research. Vetiver distillation waste has been used as a precursor for activated carbon synthesized with pyrolisis methods. Carbon is activated by a chemical process using KOH. Enhancement of amorph structure and function group by addition of zinc oxide has been characterized by Raman Spectroscopy, Fourier Transform Infra-Red (FT-IR), and X-Ray Diffraction (XRD). Furthermore, cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) has been done to show the electrochemical properties enhancement of the ZnO/AC compared to pristine AC. At the current density of 1 A/g, the specific capacitance of VRW-ACM has a value of 277 F/g. After the impregnation process, the specific capacitance of VRW-ACM-ZnO has been improved by 44.4% compared to VRW-ACM. The result showed that the activated carbon-based vetiver root waste impregnated with ZnO has the potential to be applied as supercapacitors electrodes.

Abstract: In a dye-sensitized solar cell (DSSC) the CE is responsible for the collection of electrons from the external circuit and the electrocatalysis reaction of the electrolyte. This paper reports the effect of spin-coating rate on the surface roughness, film thickness, and electrochemical properties of a Pt polymer counter electrode (CE). In this work, the spin-coating rate has been investigated in the range 1000-6000 rpm and the results indicate that low spin-coating speeds produce the thickest films with the smoothest surfaces, while high spin speeds produce thinner films with higher surface roughness. The thickness of the film decreased from 7.03 μm at 1000 rpm to 1.30 μm at 6000 rpm. Results also indicate a decrease in electrocatalysis properties and conductivity with the increase in film spin-coat rate. The resistance at the CE/electrolyte interface decreased from 9.3 Ω at 1000 rpm to 14.8 Ω at 6000 rpm. The spin-coating rate also affects the light transmittance of the CE and photovoltaic characteristics of the DSSC, such as current density and overall cell conversion efficiency. This study demonstrates a method to develop cost-effective counter electrodes for application in bifacial solar cells.

Abstract: Inkjet printing (IJP) has emerged as a promising additive manufacturing technique for fabrication of electrodes and sensors due to its cost-effectiveness compared to the traditional techniques, such as screen-printing. In this work, we present a planar, three-electrode system fabricated by inkjet printing on a polyethylene naphthalate (PEN) flexible substrate for rapid voltametric electrochemical analysis. An in-house formulation of aqueous-based gold ink with low temperature-sintering was used in printing the working and counter electrodes. The reference electrode was also inkjet-printed using a commercial silver ink and chlorinated to form an AgCl layer. Cyclic voltammetry studies using the ferri/ferrocyanide redox couple showed that the inkjet-printed electrode system has a comparable electrochemical performance to a commercial screen-printed electrode. Fabrication of a single inkjet-printed electrochemical 3-electrode platform consumes only about 0.5 mg Au and 0.2 mg Ag loading of ink with minimal waste during fabrication because of the additive nature of the printing technique. The 3-electrode platform operates with a microliter sample volume for analysis and can be used in aqueous media without delamination.

Abstract: The development of platinum-free counter electrodes (CEs) is significant in the development of cost-effective dye-sensitized solar cells (DSSCs). In this study, Pt-free, low-cost carbon black-titanium nitrate (CB-TiN) nanocomposite counter electrodes CEs were prepared via simple heating and cooling process for application in DSSCs. Different weight concentrations of CB-TiN (15-200 mg) were uniformly blended with PEDOT:PSS at 350 rpm and 150°C for 10 mins. Thereafter, the solution mixtures were immediately cooled at 4°C overnight to produce PEDOT:PSS/CB-TiN CEs. Further, to investigate the effects of iso-octyphenoxy-polyethoxyethanol (TX100) on the performance of the PEDOT:PSS/CB-TIN CE, various concentrations of TX100 (1-10%) were blended with PEDOT:PSS/15mgCB-TiN CE mixture at room temperature to produce PEDOT:PSS/15mgCB-TiN/TX100 CEs. The results indicated a gradual increase in electrocatalytic activity coupled with a reduction in internal resistance in the DSSCs as the weight of CB-TiN nanoparticles was enhanced. Similar results were obtained when the concentration of TX100 was increased. The DSSCs with the PEDOT:PSS/200mgCB-TiN and PEDOT:PSS/15mgCB-TiN/10%TX100 CEs exhibited optimum performances of 4.42% and 4.32%, respectively. Their performance closely matches that of the Pt CE (4.43%).