Modified Graphite Electrode Research Articles

Progressions in Modified Graphite Electrodes with Green Nanostructured Materials for Low Cost and Sustainable Electrochemical Detection of Environmental Contaminants

Progressions in Modified Graphite Electrodes with Green Nanostructured Materials for Low Cost and Sustainable Electrochemical Detection of Environmental Contaminants

Lead Oxide Modified Graphite Electrodes for Electrochemical Degradation of Congo Red Dye in Aqueous Solution

Lead Oxide Modified Graphite Electrodes for Electrochemical Degradation of Congo Red Dye in Aqueous Solution

Thiophene-based modified graphite electrode for the voltammetric detection of 2-aminoindane in oral fluid

New psychoactive substances, including 2-aminoindane, pose significant health risks due to their availability and structural similarity to amphetamines. Current detection methods are limited by lengthy analysis times and complex sample preparation. To address this, we present the first voltammetric determination of 2-aminoindane in oral fluid using a graphite electrode modified with a methoxyphenylthiophene-based layer. The electrochemically deposited layer was characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and both infrared and Raman spectroscopies. After the electropolymerization of methoxyphenylthiophene, the electrode was homogeneously covered with shorter oligomers of the substituted polythiophene. Cyclic and square-wave voltammetry were used to gain insight into the interaction between the modified electrode and 2-aminoindane. The modification of the electrode surface enables to record the oxidation of the primary amino group at 0.85 V, with an additional signal assigned to specific interactions being observed at 1.33 V. Determination of a 1.0 × 10–4 M 2-aminoindane concentration in oral fluids was possible, with a recovery ranging from 98 to 100%.Graphical abstract

Biochar/poly(aniline-pyrrole) modified graphite electrode and electrochemical behavior for application in low-cost supercapacitor

An attempt is made to use biochar (BC), a carbon rich low-cost green material, as a platform to house conducting polymer for fabricating stable graphite electrodes for application in next generation supercapacitor devices. Here, BC is first prepared from sucrose solution using a simple hydrothermal method. The seeded chemical oxidative copolymerization of aniline and pyrrole is then carried out at identical comonomer weight ratio using BC as seed particles. Two different BC to mixed monomer (w/w) ratios (1:0.7 and 1:1) have been used and the prepared composites are named as BC/P(Ani-Py)1:0.7 and BC/P(Ani-Py)1:1 respectively. Independent of composition, both BC seed and composite particles are spherical. The smooth homogeneous surface of BC turned heterogeneous after composite formation. The average size of BC seed particles is 2.56 µm and those of composites prepared at weight ratios of 1:0.7 and 1:1.0 are 2.72 and 2.90 µm respectively. Cyclic voltammetry (CV), galvanostatic charging discharging (GCD), and electrochemical impedance spectroscopy (EIS) are used to evaluate the electrochemical properties. Comparatively, the BC/P(Ani-Py)1:1 composite modified graphite electrode exhibited the highest capacitance value (274.27 F g−1 at a current density of 1.0 A/g) and is capable of acting as a supercapacitor electrode. A long-term cycling test of the BC/P(Ani-Py)1:1 modified electrode at a current density of 5.0 A/g displayed a capacitance retention of 96.6 % after 1000 cycles of charge and discharge, indicating a very good cycle stability.

Chemical Potency of Cobalt Doped Modified Graphite Electrode Prepared by Electrochemical Method and its Application in Degrading Solution of Rhodamine-B dye

Primary goal of the present study is to progress a methodological framework for Rhodamine-B dye degradation using cobalt doped graphite modified electrode in aqueous solution by electrochemical method. This is environmentally friendly method. Rate study for Rh-B dye degradation under various parameters like concentration, applied current and temperature were studied and compared between Graphite electrode and Cobalt graphite electrode. Ultra Violet-Visible spectral data and Chemical oxygen demand values are evident for the complete degradation of Rhodamine-B in aqueous solution during anodic oxidation using the modified Co/graphite electrode. The dye degradation efficiency for Cobalt graphite modified electrode (Co/GME) increases by 77% compared to graphite electrode. The COD values decreases to ~98% than the initial COD after degradation with Co/GME. Increase in applied current, temperature increases the rate of degradation and follows first order kinetics up to 60% of the reaction. Hydroxyl (.OH) free radicals are produced by advanced oxidation processes (AOPs), which are attack the dye molecules and cause them to degrade. SEM/EDAX is used to observe the formation of cobalt layer in the rod of graphite. Under various laboratory settings ICE values were computed, it shows that Cobalt doped graphite modified electrode acts as a good anode to degrade Rh-B dye and it converted into CO2, H2O, and other basic inorganic salts. This procedure is straightforward, inexpensive, and can be used to treat wastewater that contains organics.

Correlating Graphite Surface with Interphase for Fast‐Charging and Low‐Temperature Operation

AbstractThe properties of graphite surface can not only affect the interaction between graphite and electrolyte but also induce the formation of solid electrolyte interphase (SEI) film. Herein, the graphite surface is purposely treated to incorporate oxygen‐containing functional groups, which facilitates a desired Li2CO3‐rich SEI with high ionic conductivity and good mechanical stability. The modified graphite electrodes exhibit significant enhancement in electrochemical performance during rapid charging at the rate of 15 C, where an impressive capacity of 225 mAh g−1 is still maintained, corresponding to a capacity retention of 60.8%. Moreover, the modified electrodes showcase outstanding performance under wide temperature ranging from −50 to +65 °C, with an amazing capacity retention of 97.6% under −20 °C, the conceivable capacity of 105 mAh g−1 at −50 °C as well as excellent stability at both −20 °C and +65 °C. These findings offer valuable insights into the design of a thin and robust Li2CO3‐rich SEI layer via a facile chemical treatment of the graphite surface.

Membrane‐assisted capacitive deionization: Effect of Poly(vinyl alcohol) cross‐linking on the properties of ion exchange membranes

AbstractNovel composite electrodes were developed for application in membrane capacitive deionization (MCDI). Activated carbon (AC) was dispersed in a solution of poly(vinyl alcohol) (PVA) mixed with polyacrylic acid (PAA) or poly dimethyl diallyl ammonium chloride (PDMDAAC), and cast onto the surface of an AC‐based modified graphite electrode, prepared by phase inversion, to form a composite membrane further cross‐linked with glutaraldehyde (GA). The effect of the cross‐linking on the chemical structure of the PVA‐based membranes was determined by attenuated total reflectance Fourier‐transform infrared (ATR‐FTIR) spectroscopy. Cyclic voltammetry was conducted to examine the specific capacitance of the composite electrodes. Desalination experiments were then performed with MCDI unit cells to study the effect of cross‐linking on the desalination efficiency. It was proved that after optimization, the synthesized composite electrodes exhibited one and a half times higher NaCl removal capacity and three times higher adsorption rate as compared to that of a conventional CDI cell using commercial ion exchange membranes (IEMs) with almost the same energy consumption. The enhanced desalination performance was attributed to the optimized properties of the selected polymers and the improved adhesion of IEMs to the electrodes. This research paves the way for the application of new materials in MCDI processes for improved water desalination.

Development of Composite Nanostructured Electrodes for Water Desalination via Membrane Capacitive Deionization.

Novel two-layer nanostructured electrodes are successfully prepared for their application in membrane capacitive deionization (MCDI) processes. Nanostructured carbonaceous materials such as graphene oxide (GO) and carbon nanotubes (CNTs), as well as activated carbon (AC) are dispersed in a solution of poly(vinyl alcohol) (PVA), mixed with polyacrylic acid (PAA) or polydimethyldiallylammonium chloride (PDMDAAC), and subsequently cast on the top surface of an AC-based modified graphite electrode to form a thin composite layer that is cross-linked with glutaraldehyde (GA). Cyclic voltammetry (CV) is performed to investigate the electrochemical properties of the composite electrodes and desalination experiments are conducted in batch mode using a MCDI unit cell to investigate the effects of i) the nanostructured carbonaceous material, ii) its concentration in the polymer blend, and iii) the molecular weight of the polymers on the desalination efficiency of the system. Comparative studies with commercial membranes are performed proving that the composite nanostructured electrodes are more efficient in salt removal. The improved performance of the composite electrodes is attributed to the ion exchange properties of the selected polymers and the increased specific capacitance of the nanostructured carbonaceous materials. This research paves the way for wider application of MCDI in water desalination.

(Digital Presentation) Electrochemical Study of Mxene-Metal Oxide Composites for the Degradation of PVC-Based Microplastics

Microplastics (MPs) are fragments of any type of plastic less than 5mm in length, and it is harmful to our ocean and aquatic life. In recent years, the prevalence of MPs in aquatic environments has grown to be a serious environmental problem that has recently gained lots of attention [1, 2]. However, there is still a lack of studies on electrocatalytic treatment for an effective breakdown of MPs [3]. Here, Mxene-Metaloxide composites modified graphite electrode-based electro-fenton (EF) technology has been proposed to break down polyvinyl chloride (PVC) MPs. Advanced oxidation processes are widely studied and applied for the decomposition of MPs. Hydroxyl radicals (•OH) were generated by the electro-oxidation (EO) and electro-peroxidation (EO- ) process which has exhibited great capability for catalytic degradation of MPs and converted into H2O and CO2.In this work, electro-oxidation was carried out in a three-electrode system with an oxygen-saturated environment where Mxene-Metaloxide composites modified graphite electrode, graphite electrode, and Ag/AgCl electrode were used as a working electrode, counter electrode, and reference electrode respectively. Different operating parameters such as electrolyte type, electrolyte concentration, temperature, and reaction time were maintained for EO. Cyclic voltammetry was employed to analyze the catalytic performance of the MXene-TiO2/C modified graphite electrode in the context of the Oxygen Reduction Reaction. The obtained results revealed that the EO process can degrade 54.5% of MPs after potentiostatic electrolysis at -0.7V Ag/AgCl at 80 °C for 6 hours. Fig 1 presents the removal efficiency of PVC MPs in 0.05M Na2SO4 solution. The results from scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), UV-Vis spectroscopy, and Energy dispersive X-ray spectroscopy (EDX) revealed that the MPs degraded directly into CO2 and H2O. The results of this research showed that such a heterogeneous EF-like technology using Mxene-metal oxide composites modified graphite electrode was hoped to give an eco-friendly technique for treating MPs in wastewater.

Electrochemical detection of oxytetracycline employing sugarcane carbon modified graphite electrode.

The present study used CeO2-Co3O4 quantum dots@porous carbon/multiwalled carbon nanotube (CeO2-Co3O4 QDs@PC/MWCNT/GE) composites to modify graphite electrodes to fabricate high-sensitivity electrochemical sensors to detect the presence of oxytetracycline (OTC). The quantum dots were made from waste sugarcane bagasse. The electrochemical analysis demonstrated the superior electrochemical performance of CeO2-Co3O4 QDs@PC/MWCNT/GE, with a peak current density of 1.276mA/cm2. Electrochemical impedance spectroscopy (EIS) revealed lower impedance values for CeO2-Co3O4 QDs@PC/MWCNT/GE compared to other electrodes, indicating enhanced conductivity. The modified electrode exhibited an enlarged electrochemically active area, with values of 0.602 cm2, almost seven times that of the bare graphite electrode (0.079 cm2). The results showed that the CeO2-Co3O4 QDs@PC/MWCNT/GE had excellent performance for OTC detection, and its linear calibration range was 1.007 × 10-8 to 2.04 × 10-7M (i.e., 0.005-0.1ppm) and 1.007 × 10-6 to 1.209 × 10-4M (i.e., 0.5-60ppm). The limit of detection and limit of quantification were 1.23nM (0.61ppb) and 4.09nM (2.03ppb) (S/N = 3), respectively. The electrode demonstrated long-term stability for up to 7weeks. This method provides a new way to prepare electrochemical sensors for OTC detection.

Electrochemical Behavior and Electrical Stability of a Needle-Shaped Zinc Metal-Organic Framework Modified Graphite Electrode

In this paper, a novel needle-shaped Zinc organic framework was formed on the surface of a functionalized graphite electrode (Zn-MOF/CE) to create a methodical alternative electrode. The characterization of the Zn-MOF modifier was investigated via XRD, FT-IR, FESEM-EDS mapping, and N2 sorption. The redox behavior of the modified electrode was examined, showing high stability and conductivity under a diffusion-controlled process as a desirable working electrode. Also, the redox process of hydroquinone, as an organic molecule model, at the surface of the modified electrode was investigated and its operation was optimized and modeled by the central composite design (CCD) method. Based on the obtained results and CCD model, the process exhibited the best performance in scan rate 560 mV/s, pH= 9.9. Moreover, the frequency domain using bode plots, and two identical electrical models were evaluated by CCD results that could be employed in stability and electrode material performance prediction.

Synthesis of LaW/Ag/GNRs nanocomposite: Application as transducer material for the simultaneous nano molar detection of synthetic dyes and as anode material for Li ion batteries

In this present research, we have synthesized the lanthanum tungstate/silver nanoparticle/graphene nanoribbons (LaW/Ag/GNRs) nanocomposite as a novel system for the simultaneous electrochemical determination of two synthetic food colorants sunset yellow (SY) and acid yellow (AY). The synthesised nanocomposite modified graphite electrode (Gr) provides the presence of more active sites for the transfer of electrons, allowing for a stronger voltametric response that is due to the faster rate of electron transfer from the analytes. The as-synthesized nanocomposite was characterized by different analytical methods. The enhanced anodic peak currents represented the excellent analytical performance for simultaneous detection of SY and AY in the range of 20 nm to 450 nM, with a low limit of detection (LOD) of 0.025 nm for SY and 0.050 nM for AY. This proposed sensor showed excellent recovery values real sample analysis. Further the nanocomposite was used as the anode material in Li ion batteries and was evaluated in an aqueous saturated Li2SO4 electrolyte. In terms of cycle performance, enhanced rate capability, and high discharge capacity, LaW/Ag/GNRs nanocomposite has made significant advancements. The lithiated LaW/Ag/GNRs nanocomposite half-cell vs. SCE offers a 227.86 mA h g−1 capacity up to 10 cycles at 0.08 mA. In the potential range of 1.0 to 0.0 V, the whole cell configuration LaW/AgNPs/GNRs|aq.saturated Li2SO4|LiMn2O4 produced a discharge capacity of 240.24 mA h g−1. With 96.95% columbic efficiency, the battery performance of the cell has greatly boosted. This excellent result clearly fits this material as an anode in future aqueous rechargeable lithium batteries for energy technology.

Silver nanostructure-modified graphite electrode for in-operando SERRS investigation of iron porphyrins during high-potential electrocatalysis.

In-operando spectroscopic observation of the intermediates formed during various electrocatalytic oxidation and reduction reactions is crucial to propose the mechanism of the corresponding reaction. Surface-enhanced resonance Raman spectroscopy coupled to rotating disk electrochemistry (SERRS-RDE), developed about a decade ago, proved to be an excellent spectroscopic tool to investigate the mechanism of heterogeneous oxygen reduction reaction (ORR) catalyzed by synthetic iron porphyrin complexes under steady-state conditions in water. The information about the formation of the intermediates accumulated during the course of the reaction at the electrode interface helped to develop better ORR catalysts with second sphere residues in the porphyrin rings. To date, the application of this SERRS-RDE setup is limited to ORR only because the thiol self-assembled monolayer (SAM)-modified Ag electrode, used as the working electrode in these experiments, suffers from stability issues at more cathodic and anodic potential, where H2O oxidation, CO2 reduction, and H+ reduction reactions occur. The current investigation shows the development of a second-generation SERRS-RDE setup consisting of an Ag nanostructure (AgNS)-modified graphite electrode as the working electrode. These electrodes show higher stability (compared to the conventional thiol SAM-modified Ag electrode) upon exposure to very high cathodic and anodic potential with a good signal-to-noise ratio in the Raman spectra. The behavior of this modified electrode toward ORR is found to be the same as the SAM-modified Ag electrode, and the same ORR intermediates are observed during electrochemical ORR. At higher cathodic potential, the signatures of Fe(0) porphyrin, an important intermediate in H+ and CO2 reduction reactions, was observed at the electrode-water interface.

Insights into the Enhanced Reversibility of Graphite Anode Upon Fast Charging Through Li Reservoir.

Increasing the charging rate and reducing the charging time for Li-ion batteries are crucial to realize the mainstream of electric vehicles. However, it is formidable to avoid the Li plating on graphite anode upon fast charging. Despite the tremendous progress in Li detection techniques, the fundamental mechanism of Li plating and its chemical/electrochemical responses upon cycling still remains elusive. Herein, we present a comprehensive electrochemical method to investigate the fast charging behavior of graphite electrode. A detailed analysis is directed toward understanding the changes in phase, composition, and morphology of the fast-charged graphite. By applying a resting process, we scrutinize the further reactions of the plated Li, which readily transforms into irreversible (dead) Li. We further develop a modified graphite electrode with a thin Ag coating as the Li reservoir. The plated Li can be "absorbed" by the Ag layer to form the Li-Ag solid solution that suppresses the formation of dead Li and provides structural stability, thus promoting the further lithiation of graphite and enhancing the reversibility. This work not only provides additional insights into the fast charging behavior of graphite electrode but also demonstrates a potential strategy to improve the fast charging performance of graphite anode.

Electro-immunosensor for ultra-sensitive determination of cardiac troponin I based on reduced graphene oxide and polytyramine.

This work reports the construction of a novel nanostructured immunosensor for detection of the troponin I biomarker (cTnI). Anti-troponin I antibody was anchored on the modified graphite electrode with reduced graphene oxide and polytyramine for detection of troponin I in serum samples. The performance of the electro-immunosensor was evaluated by differential pulse voltammetry. The immunosensor presented a wide work range, from 4ng mL-1 to 4pg mL-1 , whose detection limit (4pg mL-1 ) is significantly lower than the basal level in human serum, and maintained 100% of response after 30 days of storage. Moreover, the immunosensor showed good selectivity for detection of cTnI in real sample containing interfering substances and specificity of response to cTnI in the serum of healthy and sick patients, and demonstrated the possibility of reuse for two consecutive analyses, in addition to using a simplified and inexpensive platform when compared to other devices, demonstrating them excellent potential for application in diagnosis in the early stages of acute myocardial infarction.

Development of modified graphite electrodes with nanoparticles and their application in the quantification of sucrose

AbstractBACKGROUNDDeveloping fast and reliable methods with little sample preparation has become increasingly important for process monitoring and control. Electrochemical methods stand out for their low cost and instrumental simplicity. Furthermore, electrodes with nanoparticles can improve the method's sensitivity and specificity. This study developed carbon paste electrodes modified with nanoparticles of copper and iron. In addition, cyclic voltammetry was performed using a low‐cost potentiostat designed for a Raspberry Pi single‐board computer. As a proof of concept, the constructed electrodes were tested with ferrocyanide and applied to quantify sucrose, and their performance was compared to that of the glassy carbon electrode.RESULTSThe nanoparticles were successfully synthesized, as confirmed by morphology and physicochemical characterization. Based on the adjusted R2, the electrode made with the addition of copper oxide nanoparticles has a similar performance to the commercial glassy carbon electrode. All electrodes' root mean square error (RMSE) values were approximately 10−4 mol L−1. The lowest values for the inverse of the analytical sensitivity for sucrose were obtained for the unmodified carbon paste electrode (9.54 × 10−6 mol L−1) and copper oxide nanoparticles electrode (5.30 × 10−6 mol L−1). These electrodes also had the lowest limits of detection (10−5 mol L−1) and, for the limit of quantification, all electrodes had similar values (10−2 mol L−1).CONCLUSIONIn general, superior performance of carbon paste electrodes was observed concerning the commercial glassy carbon electrodes. Compared to previous studies, the developed electrodes showed good sensitivity and the low cost of the electrochemical system stands out as the main advantage. © 2022 Society of Chemical Industry (SCI).

Aryl Diazonium- and Pyrene-Functionalised Graphite for Lithium-Ion Batteries

One of the main reasons for battery aging in lithium-ion batteries (LIBs) is the formation of a solid electrolyte interphase (SEI). SEI formation results in capacity loss and power fading due to irreversible electrochemical decomposition of electrolyte. However, the SEI protects the negative electrode from further parasitic surface reactions with the electrolyte. Therefore, it is of great interest to learn more about factors influencing the SEI and its formation. One approach is to modify the surface of the active material.Since graphite is commonly used as negative electrode material in LIBs, we modified graphite with anchor molecules featuring functional groups. In particular, we use aryl diazonium salts and pyrenes as anchor molecules to cover a covalent and a non-covalent approach. The influence of different functional groups on the electrochemical properties of graphite electrodes is investigated. Furthermore, the importance of the modification method and the influence of the anchor molecule is addressed. The functional groups of modified graphite electrodes enable further layer growth, which is an important aspect for the design of an artificial SEI.For surface and electrochemical characterisation of the modified graphite samples, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV) and galvanostatic cycling are used.Financial support of the German Research Foundation (DFG) within the project B2 of the Collaborative Research Centre (SFB 1176) is kindly acknowledged.

Rod shaped zirconium titanate nanoparticles: Synthesis, comparison and systematic investigation of structural, photoluminescence, electrochemical sensing and supercapacitor properties

ZrTiO4 (ZTO) nanoparticles (NPs) are synthesized by solution combustion method using chemical fuel (Glycine) (ZTOG) and green (Aloevera) extract (ZTOA) as a reducing agent (15–25 ml) and calcined at 700 °C. The synthesized samples are characterized and its multi-functional properties such as Photoluminescence, Sensor and Supercapacitor properties were discussed in detail. Powder X-ray diffraction pattern of ZTOG and ZTOA shows the Bragg's reflection corresponding to ZrTiO4. The pure orthorhombic phase is retained in ZTOA whereas in ZTOG, monoclinic and cubic phases are observed. The crystallite size estimated by PXRD matches well with TEM analysis. From the Wood and Tauc's relation, the energy band gap was found to be 2.8 and 3.2 eV which was further confirmed by band structure using density of states. The photoluminescence emission peaks (λ = 350 nm), CIE and CCT of ZTOA and ZTOG clearly confirms that the present nanophosphor might be a good nanophosphor material for blue light emitting diodes. X-ray/Gamma ray absorption properties are also studied which clearly shows the ZrTiO4 might be a good absorbing material. Furthermore, Cyclic voltammetry (CV) analysis of ZTOA nanorods shows very good redox peaks as compared to ZTOG. From the Electrochemical Impedance Spectroscopy (EIS) measurements, the charge-transfer resistance for prepared nanorods ZTOA and ZTOG was found to be 180 and 261 Ω respectively. The modified graphite electrode with ZTOA shows good sensing activity for both paracetamol and ascorbic acid rather than ZTOG.

The electro-oxidation of primary alcohols via a coral-shaped cobalt metal–organic framework modified graphite electrode in neutral media

The electro-oxidation of alcohols into corresponding aldehydes achieved enormous attention. However, numerous challenges remain in exploring catalytic systems with high conversion efficiency and selectivity. Considering the worldwide attention toward metal–organic frameworks (MOFs) as outstanding crystalline porous materials, many chemists have been encouraged to use them in organic transformations. In this study, a novel coral-shaped cobalt organic framework was grown onto the surface of a functionalized graphite electrode (Co-MOF/C) to fabricate an efficient modified electrode in the electro-oxidation alcohols. The modified Co-MOF/C electrode showed high stability, large surface area, rich pores, and good conductivity as a desirable water-stable working electrode for selective oxidation of alcohols into aldehydes in good to excellent yields under a diffusion-controlled process.

Catalytic Properties of Free-Base Porphyrin Modified Graphite Electrodes for Electrochemical Water Splitting in Alkaline Medium

Hydrogen generation via electrochemical water splitting is considered an eco-friendly pathway for obtaining this desired alternative energy source, and it has triggered an intensive search for low cost and efficient catalysts. Within this context, four free-base porphyrins were studied as heterogeneous catalysts for the oxygen and hydrogen evolution reactions (OER and HER) in alkaline aqueous solutions. TEM and STEM analyses of samples obtained by drop-casting the porphyrins from different organic solvents on TEM grids revealed a rich variety of aggregates due to the self-assembling property of the porphyrin molecules. Modified electrodes were manufactured by applying the four tetrapyrrolic macrocycles from various solvents on the surface of graphite supports, in one or more layers. Experiments performed in 0.1 M and 1 M KOH electrolyte solutions allowed the identification of the most electrocatalytically active electrodes for the OER and HER, respectively. In the first case, the electrode was manufactured by applying three layers of 5-(4-pyridyl)-10,15,20-tris(4-phenoxyphenyl)porphyrin on the graphite substrate from N,N-dimethylformamide solution was identified as overall catalytically superior. In the second case, the electrode obtained by applying one layer of 5,10,15,20-tetrakis(4-allyloxyphenyl)-porphyrin from benzonitrile solution displayed an HER overpotential value of 500 mV at i = −10 mA/cm2 and a Tafel slope of 190 mV/dec.