CeO2 Nanocomposites Research Articles

An antioxidant nanodrug protects against hepatic ischemia-reperfusion injury by attenuating oxidative stress and inflammation.

Liver transplantation is currently recognized as the only effective therapeutic option for end-stage liver disease. Hepatic ischemia-reperfusion injury (IRI) remains a major cause of graft damage or dysfunction, and is mediated by the abundant production of reactive oxygen species (ROS) and a complex cascade of inflammation during the reperfusion period. However, no universal antioxidant has been applied in clinical practice due to its low bioavailability and non-specific targeting. Herein, cerium oxide and manganese oxide nanocomposites (CM NCs), with the advantages of high biocompatibility, passive liver-targeting and short-term metabolic excretion, were synthesized as a nanodrug for hepatic IRI therapy. The CM NCs exhibited excellent superoxide dismutase (SOD) and catalase (CAT) mimetic activity to scavenge ROS and generate oxygen (O2). Therefore, CM NCs could alleviate oxidative stress, subsequently suppress the activation of Kupffer cells (KCs) and neutrophils, and reduce the secretion of inflammatory factors due to the synergistic effect of ROS scavenging and O2 production. By exploring the underlying mechanisms of the CM NCs in the treatment of hepatic IRI, we suggest that the CM NCs with ROS scavenging and inflammation regulation capacity show clinical potential for hepatic IRI management and provide new perspectives in the treatment of other oxidative-stress-related diseases.

Enhanced Dielectric Constant and Mechanical Investigation of Epoxidized Natural Rubber with Tm-Doped Ceo2 Nanocomposites

Enhanced Dielectric Constant and Mechanical Investigation of Epoxidized Natural Rubber with Tm-Doped Ceo2 Nanocomposites

Synergetic effect of adsorption-photocatalysis by [formula omitted]nanocomposites for photodegradation of doxorubicin

The photodegradation of DOX is investigated by adsorption-photocatalysis synergy. Graphene oxide - cerium oxide (GO−CeO2) nanocomposites have been synthesized and their structural, optical, and morphological properties are investigated. The synthesized GO−CeO2nanocomposites are highly crystalline and exhibit lower optical bandgap energy of 3.2 eV, a narrow particle size distribution of 7–11 nm. The UV–Vis spectroscopy data suggests that 97% of DOX is removed within 360 min by the adsorption-photocatalysis synergy. The pH of the DOX solution widely affected the removal process; neutral and alkaline conditions of pH supported the degradation process. GO−CeO2 nanocomposites exhibited preferable performance stability and retained the removal efficiency even after the fifth cycle of removal. The enhanced photocatalytic activity of the GO−CeO2is attributed to the lower bandgap energy and interfacial charge transfer at the heterojunction of GO matrix and anchored CeO2nanoparticles. Furthermore, the degradation of DOX in presence of co-existing ions and organic dyes was also studied. The influence of coexisting ions showed higher order of removal efficiency for monovalent ions as compare to divalent ions. Similarly, within the presence of cationic dye, the removal process of DOX was found prominent. The high-performance liquid chromatography (HPLC) analysis confirmed 99.8% removal efficiency in 420 min which indicates complete eradication of DOX without any secondary pollution. Hence, the GO−CeO2a photocatalytic adsorbent with higher stability and recyclability would provide a cost-effective and eco-friendly approach for the mitigation of DOX without any secondary toxic metabolites.

Single-atom Au catalyst loaded on CeO2: A novel single-atom nanozyme electrochemical H2O2 sensor

Owing to the maximum utilization efficiency of the metal atoms, single-atom catalysts (SACs), which have higher catalytic activity and selectivity than traditional nanocatalysts, have been used as sensing materials for signal amplification and sensitive detection of biomolecules. Recently, single-atom Au catalysts have attracted attention. Au nanoparticles have high catalytic activity, and the loading efficiency on the support can be further increased by downsizing Au nanoparticles to single atoms. Compared with other oxide supports, the higher density of vacancies on the CeO2 surface can accommodate more Au atoms, and thereby CeO2 can stabilize more metal atoms. In this paper, we describe an electrochemical sensor based on Au–CeO2 nanocomposites for ultrasensitive and highly selective detection of H2O2 released from A549 cells by immobilizing single-atom Au on specific facets of CeO2. Due to the abundant oxygen vacancies on the surface and the strong interactive effect between Ce ions and Au atoms, this sensor displayed excellent electrochemical performance, with a detection limit of 1.4 nM. The synergistic effect of CeO2 and Au atoms also resulted in high catalytic activity and stability. This study shows that the single-atom nanozyme sensing strategy can be applied to the sensitive detection of reactive oxygen species. Thus, single-atom sensors have broad application prospects in clinical analysis and physiology.

Efficient degradation of orange II by core shell CoFe2O4–CeO2 nanocomposite with the synergistic effect from sodium persulfate

Novel core shell CoFe2O4–CeO2 (CoFe–Ce) nanocomposite was synthesized and investigated as an efficient photocatalyst to activate sodium persulfate (Na2S2O8, PS) for orange Ⅱ (OⅡ) degradation. The CoFe–Ce nanocomposite was successfully designed and synthesized by a facile hydrothermal reaction followed by calcination and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), ultraviolet–visible diffuse reflectance spectroscopy (UV–Vis DRS), and vibrating sample magnetometer (VSM). Compared with pure CoFe2O4 and CeO2, the photocatalytic efficiency of CoFe–Ce nanocomposite was significantly improved. Under the irradiation of visible light, the catalytic degradation efficiency of orange II could reach to 98.5% within 60 min. Additionally, the as-prepared material could be recycled for at least five times using magnetic separation ability of the nanocomposite, and during the cycling the dye degradation rate was almost unchanged. The active species produced during the degradation were studied by classical quenching experiments, and the different types of free radicals produced in the system were further confirmed by electron paramagnetic resonance (EPR) spectroscopy. This novel nanocomposite is expected to have potential application for degradation of organic pollutants in wastewater by utilizing solar energy.

Degradation of Orange II by Fe2O3 and CeO2 nanocomposite when assisted by NaHSO3

Fe2O3@CeO2 nanocomposites were synthesized by water bath heating method to activate NaHSO3 for Orange II dye (50 mg L−1) degradation, which reached up to 98.2% within 120 min. The Fe2O3@CeO2 and NaHSO3 dosages and the molar ratios of Ce and Fe in Fe2O3@CeO2 were investigated to obtain the optimum conditions as follows: 0.02 g Fe2[email protected]2, 0.1 g NaHSO3 and the molar ratio of Ce and Fe was 5:2 (designated as Ce-Fe-1, or simply Fe2O3@CeO2). In addition, Fe2O3@CeO2 catalyst displayed superior catalytic performance to those materials that were previously reported, as verified by the good stability (reached 90.9% after three cycles) and high degradation rate of Orange II (98.2%) of the currently developed material. Existence of ·SO4– and ·OH radicals were verified by Electron Spin Resonance Spectroscopy during degradation, and these radicals are proposed to have high degradation efficiency of Orange II. On the basis of the detected radicals, a possible degradation mechanism was proposed to provide more choices for the application of sulfite in advanced oxidation processes (AOPs).

Application of a novel nanocomposite containing micro-nutrient solubilizing bacterial strains and CeO2 nanocomposite as bio-fertilizer

Chemical fertilizers are used in modern agricultural practice to increase plant output. They possess anthropogenic compounds which are hazardous, result in poor soil quality, poor crop nutrition and pollutes the water table. Currently, food crops that lack in micro-nutrients (Zn, silicates and Se) can be enriched with micronutrients by use of fertilizers. Eco-friendly bio-fertilizers have been proved to provide a known population of microorganisms that create a mutual benefit to the plants & the rhizosphere soil. Nanomaterials are often used in plant fertilizer formulation, allowing for controlled release and targeted delivery of beneficial nanoscale components, as well as to boost plant production and reduce environmental pollutants. In the present study we identified a multipotent micronutrient solubilizing bacterium (MSB) - Pseudomonas gessardi and Pseudomonas azotoformans as a bio-fertiliser. Comparative study of the formulated MSB, with nanocomposite prepared with the soya chunks as natural carrier material and chemically synthesized cerium oxide was performed on the growth of fenugreek for its effectiveness. The SEM images of nanocomposite showed the non-uniform distribution of CeO2 in bio-inoculant with an average size of 25.24 nm. The current study deals with increase in the shoot and root length of the fenugreek plant with only 75 ppm of CeO2 in nanocomposite, thereby preventing bioaccumulation of Ce in soil. This work gives a potential use of CeO2 nanocomposite with MSB bio-inoculants which could be applied to soil deficient with the micronutrients that can enhance the crop yield.

Highly Active PdO/Mn3 O4 /CeO2 Nanocomposites Supported on One Dimensional Halloysite Nanotubes for Photoassisted Thermal Catalytic Methane Combustion.

In this work, we have successfully triggered the aqueous auto-redox reactions between reductive Ce(OH)3 and oxidative MnO4 - /Pd2+ ions to form PdO/Mn3 O4 /CeO2 (PMC) nanocomposites. PMC could spontaneously self-assemble into compact encapsulation on the surface of halloysite nanotubes (HNTs) to form the final one dimensional HNTs supported PMCs (HPMC). It is identified that there exists strong synergistic effects among the components of PdO, Mn3 O4 , and CeO2 , and hence HPMC could show excellent performance on photoassisted thermal catalytic CH4 combustion that its light-off temperature was sharply reduced to be 180 °C under visible light irradiation. Based on detailed studies, it is found that the catalytic reaction process well follows the classic MVK mechanism, and adsorption/activation of O2 into active oxygen species (O*) should be the rate-determining step for CH4 conversion.

Investigation of electrochemical performance of an efficient Ti2O3–CeO2 nanocomposite for enhanced pollution-free energy conversion applications

The development of an economical, abundant, stable, and greatly active electrocatalyst for water oxidation is extremely important for future energy conversion system. Electrochemical water splitting is a new move toward H2 and O2 gas production. It can be used in sustainable and pollution-free energy conversion applications. In this work, Ti2O3–CeO2 nanocomposites were successfully synthesized with different molar ratios by facile hydrothermal method for electrochemical water oxidation. Mixed phase structure of Ti2O3–CeO2 nanocomposites was confirmed by X-ray diffraction spectra and well identified by highest peak of Ti2O3 in 2θ values of 33.0 and CeO2 in 2θ values of 28.5. The characteristic peaks from Raman and photoluminescence spectroscopy further confirmed Ti2O3–CeO2 nanocomposite formation. Existence of multidimensional nanostructures such as nanoparticles and small nanocubes of Ti2O3–CeO2 nanocomposites were investigated by scanning electron microscope images. Mesoporous nature of Ti2O3–CeO2 nanocomposites was further analyzed by Brunauer–Emmett–Teller analysis. The high surface area could benefit the Ti2O3–CeO2 nanocomposites with greatly improved oxygen evolution reaction (OER) performance. In three molar ratios, 1:3 M ratios of Ti2O3–CeO2 nanocomposites showed high catalytic action at overpotential of 244 mV. The best OER electrocatalyst was obtained by 1:3 M ratios of Ti2O3–CeO2 nanocomposites, which exhibited high current density and high specific capacitance values of 238 mA/g and 517 F/g, respectively. Therefore, Ti/Ce molar ratio played a crucial role in enhancing the OER performance.

Enhanced photo-Fenton activity over a sunlight-driven ignition synthesized α-Fe2O3-Fe3O4/CeO2 heterojunction catalyst enriched with oxygen vacancies

The use of catalysts with several degradation mechanisms has emerged as a promising technique for advanced water treatment. Herein, a ternary α-Fe2O3-Fe3O4/CeO2 nanocomposite is synthesized using a sunlight-driven ignition method for the photo-Fenton degradation of organic dyes under sunlight irradiation. The fabrication of the nanocomposite using this method facilitates the introduction of oxygen vacancies on its surface, which enables the occurrence of multiple degradation mechanisms. The oxygen vacancies prolong the photogenerated charge recombination and expedite the redox cycle between Fe3+/Ce4+ and Fe2+/Ce3+. The effective construction of the α-Fe2O3-Fe3O4/CeO2 heterojunction catalyst enriched with oxygen vacancies is confirmed using different powerful analytical techniques. α-Fe2O3-Fe3O4/CeO2 shows higher photocatalytic activity toward the degradation of methylene blue (MB) than CeO2, α-Fe2O3, and α-Fe2O3-Fe3O4, which can be attributed to the enhanced light absorption in the visible region along with the improved charge separation among the components of the heterojunction through the oxygen vacancies. An inspection of the sample in the presence of H2O2 reveals that the degradation of MB dye is enhanced by 2.6 times, confirming the photo-Fenton catalytic process. Photoluminescence and active species trapping experiments evidence the role of •OH, •O2−, and 1O2 in the degradation of the dye. A synergistic mechanical pathway is proposed to explain the improved photo-Fenton reaction of the synthesized heterojunction composites.

Novel, Low Cost and Fast Detection Sensor for Biogenic H2S Gas Based on Polyaniline/ZnO, CdO and CeO2 nanocomposites at Room Temperature

Screen printed electrode (SPE) is considering one of the most prospective techniques for sensing purposes due to its low cost, easy fabrication and reusability. It is worthwhile to use SPE as a sensor for fast detection of the biogenic H2S gas which is a sign for sulfate-reducing bacteria (SRB) existence. SRB presence is the first indicator in the industrial sector that causes a catastrophic environmental issue which give time for the decision makers to avoid their consequences. Polyaniline (PANI), PANI/MOx nanocomposites were prepared as sensing materials. The prepared materials have been characterized by FT-IR, Raman spectroscopy and GPC techniques. The morphological properties have been determined using SEM and HR-TEM. The particle size distributions have been determined using dynamic light scattering (DLS). Moreover, the fabricated sensors also have been applied as biogenic H2S gas detector using the electrical resistance changes. The data confirmed that the PANI doped with ZnO NPs has the best sensing performance compared to the other fabricated sensors.

Structural and spectroscopic characterizations of boron doped TiO2–CeO2 nanocomposite synthesized by solution combustion technique for photocatalytic applications

Boron doped TiO2CeO2 (B/TiO2CeO2) nanocomposite has been synthesized using solution combustion technique. The prepared sample has been heated at different temperatures and characterized using a variety of diffractometric and spectroscopic techniques such as X-ray diffraction (XRD), Field Emission scanning electron microscopy (FE-SEM), UV-vis absorption, X-ray Photoelectron spectroscopy (XPS). XRD analysis reveals the phase transformation of the sample from anatase to rutile at 700 °C. FE-SEM image shows the porous structure with uniform pore distribution and the nanoparticles spread in them at the surface of B/TiO2CeO2 nanocomposite. The absorption edge of the nanocomposite samples exhibit both red shift and blue shift as evidenced by the UV–visible absorption spectra. From XPS measurements, it is clear that the doped boron enters both substitutionally and interstitially into TiO2CeO2 nanocomposite. XPS results show the decrease in binding energy of Ti 2P3/2 from 459.0 eV to 458.62 eV, an indication for the reduction of titanium from Ti4+ state to low-valence Tix+ species. The observed higher intensity of Ce3+ XPS peaks indicates the possible formation of oxygen vacancies in these composites.

PANI/g-C3N4/CeO2 Nanocomposite for Photodegradation of Diazinon in Aqueous Solution

Diazinon is one of organophosphate pesticides which it is classified as a relatively dangerous substance (Class II by WHO). The PANI/g C3N4/ CeO2 nanocomposite was synthesized by in situ polymerization method to determine the efficiency of photocatalytic degradation of diazinon. The photocatalytic activities efficiencies of the supported and unsupported nanocomposites were evaluated using diazinon as a model pollutant. The superior photocatalytic effect of the PANI/g C3N4/CeO2 nanocomposite is attributed to the synergistic effect of PANI and g C3N4/CeO2 which promotes migration efficiency of the photogenerated carriers on the g C3N4/CeO2 nanocomposite interface. The effects of pH, initial diazinon concentration, catalyst load, hydrogen peroxide as well as effect of other organic compound were investigated using photocatalytic degradation of PANI/g C3N4/CeO2. The results obtained indicate the efficient degradation at pH= 6 which extent to 94.08 %, at 10 ppm extent to 88.9%, at 0.1 g/L extent to 97.48 %; were as increasing the concentration of hydrogen peroxide, the percent of degradation of diazinon increased due to the increased reaction between hydrogen peroxide and electron in the conduction band of PANI/g-C3N4/CeO2. Hydrogen peroxide can effectively inhibited electron hole recombination. Therefore hydrogen peroxide is better electron acceptor than dissolved oxygen; it acts as an alternative electron acceptor to oxygen. The effect of different organic compound on the photocatalytic degradation of diazinon; organic compound such as phenol, citric acid, EDTA and oxalic acid were examined, the result indicated that photocatalytic degradation was negatively affected in the presence of all organic compounds.

Manganese-doped cerium oxide nanocomposite as a therapeutic agent for MCF-7 adenocarcinoma cell line

The preparation of a manganese-doped cerium oxide (Mn:CeO2) nanocomposite via hydrothermal route is described. Cubic fluorite structure of single phase was exhibited by studying structural analysis through x-ray diffraction (XRD) technique and morphological analysis was conducted by scanning electron microscope. Surface analytic technique of energy dispersive x-ray spectroscopy (EDX) was conducted to analyze the relative amount of any impurity and doping. Structural changes due to manganese doping such as increment in production of vacancies of oxygen within crystal of cerium oxide, and reduction in size of crystallite and constant of lattice was observed in our research study. Moreover, the Mn:CeO2 nanocomposite demonstrates differential cytotoxicity against MCF-7 adenocarcinoma cell line, which renders it a promising candidate for targeted cancer therapy. The anti-tumorous activity of the cerium oxide nanocomposite was significantly enhanced with doping of manganese, which is directly linked with the generation of highly reactive oxygen facets. The experimental results are supported by a mathematical model that confirms a confidence level of 95%. This research has paved the way for many utilities in therapeutics and magnetic resonance imaging diagnostics through new observations, and hence verified their math model.

ZrO2–CeO2 assimilated electroless Ni–P anti-corrosion coatings

ZrO2–CeO2 nanocomposites are well known for their superior mechanical, thermal and tribological properties. On the other hand, Ni–P electroless coatings are in widespread industrial usage. In this work, we attempted to assimilate the lab-made ZrO2–CeO2 nanocomposite into Ni–P electroless coating to achieve synergistic property enhancement through composition optimization. Several techniques thoroughly characterized both the as-prepared nanocomposite powder and the Ni–P–ZrO2–CeO2 composite coating. The results proved that the nanocomposite assimilation refined coating surface morphology and boosted mechanical, tribological and corrosion resistance properties. Post-high-temperature annealing at 350 °C, significantly improved the coating performance, which was attributed to the annealing induced morphology refinement and crystallization.

Improvement the catalytic activity of activated Au/GO–CeO2 nanocatalysts by facile ball milling–hydrothermal methods for PROX operation

Gold-based nanocatalysts have proved to be an appropriate candidate for the selective preferential CO oxidation (PROX) in H2-containing atmosphere. Effectiveness of small gold nanoparticles in the presence of immobilized on GO–CeO2 nanocomposites was investigated by a range of ball milling conditions for the PROX reaction. First, GO–CeO2 nanocomposites were fabricated using the combination of ball milling and hydrothermal methods, and then, the gold nanocomposites were activated at 400 ± 2 °C for 4 h in Ar atmosphere. Next, Au/GO–CeO2 catalysts were synthesized, and after that, the gold nanocontents calcined at 400 ± 2 °C in Ar gas during 4 h. The catalytic activity and selectivity of activated gold catalysts (Au/GO–CeO2) were studied for the preferential CO oxidation at optimized conditions from the ambient temperature to 175 ± 2 °C. The gas and vapor phase components were analyzed by a Fourier Transform Infrared Spectroscopy. The effects of ball mill’s parameters, such as milling time, bead amounts, loading percentage, and milling temperatures, on the catalytic activity and selectivity of gold catalysts were investigated. Under relatively optimized conditions, the results showed the high conversion (C%: 97) and selectivity (S%: 92) for the gold nanocatalysts at 150 °C reaction time towards CO2 as the main product when the Au/GO–CeO2 nanocatalysts were synthesized by the use of 12% of GO solution with 90 zirconia oxide balls at 70 °C for 8 h of the ball milling condition.

Removal of arsenic from water through ceramic filter modified by nano-CeO2: A cost-effective approach for remote areas

The groundwater with high arsenic concentration is widespread, especially in many remote areas of developing countries. Arsenic existing in drinking water sources has a high risk to human health. In this study, an innovative effort to remove As(V) from water using ceramic filters functionalized with CeO2 nanocomposites (CF-CeO2) was investigated. Considering removal efficiency and flow rate, the suitable coating amount of CeO2 was determined for the production of CF-CeO2. Based on the factorial analysis, influent arsenic concentration and pH were found to be significant factors in As(V) removal. Furthermore, CF-CeO2 exhibited a good removal capability over a wide pH range and was insensitive to the change of background electrolyte concentration. In the treatment of natural water, the existence of medium and low turbidity levels facilitated As(V) removing, while the high turbidity level exhibited the opposite effect. Based on macroscopic experiments and microscopic characterizations, it was revealed that the As(V) removal mechanism by the CF-CeO2 mainly included ion-exchange and electrostatic attraction. The findings in this study provided convincing evidence for the use of CF-CeO2 as a high-efficiency, low-cost, and safe approach for water purification in the remote areas of developing countries.

CeO2 nanoparticles modified by CuO nanoparticles for low-temperature CO oxidation with high catalytic activity

CeO2 nanocomposites modified by CuO are successfully synthesized by a facile hydrothermal method. The influence of different Cu contents on the crystal structure, morphology, surface element valence, specific surface area, and material reduction temperature has been characterized by many different technical characterization means of XRD, SEM, TEM, Raman, XPS, specific surface area measurement and temperature programmed control under hydrogen, respectively. With the increasing of Cu metal content, the grain size tends to decrease and specific surface area of the sample tends to increase. The CO catalytic oxidation performance of CuO–CeO2 nanocomposites is studied by gas chromatography. Compared with pure CeO2, the CuO–CeO2 nanocomposite catalysts showed more active catalytic performance. The temperature with catalyst rate of 50% in all CuO–CeO2 nanocomposite catalysts for CO conversion is relatively low (77 < T50 < 172 °C). In all as-prepared nanocatalysts, the CuO–CeO2 nanocomposite catalyst with 30 wt% Cu plays the best catalytic activity and the temperature of 50% CO conversion could be down to 77 °C. The introduction of transition metal element Cu could facilitate the interaction of the material surface, promoting the generation of oxygen vacancy, so as to improve the conversion efficiency of CuO modified CeO2 nanocomposite for CO catalytic oxidation at low temperature.

Effect of Cr doping in CeO2 nanostructures on photocatalysis and H2O2 assisted methylene blue dye degradation

Optimization of Advanced Oxidation Processes (AOPs) is key for the demand in green and sustainable method for degradation of organic contaminants in aqueous solution. In this study, the effect of Cr doping on CeO2 nanostructure was investigated to evaluate the catalytic performances of the Cr doped CeO2 nanocomposites with Methylene Blue (MB) used as model contaminant. Two types of AOPs were also explored; photocatalysis and H2O2 assisted. The Cr-doped CeO2 samples were prepared by deposition precipitation method and characterized with XRD, FE-SEM-EDX, UV–vis Spectroscopy and TPR. Generally, increase in Cr doping improved the catalytic activity in MB degradation efficiency for photocatalysis and H2O2-assisted methods, where with 3% weight of Cr-doping achieved 41 % and 59 % of MB degradation across 100 min respectively. The improvement of catalytic activity was attributed to the effects on Cr doping, which lowers the CeO2 band gap and also the Cr species serving as electron trapping centers to slow down the recombination of the charge carriers. The MB degradation results also showed that for Cr-doped CeO2 system, H2O2-assisted was the more effective catalytic method compared to photocatalysis. Isopropanol has been found explicitly feasible to demonstrate a plausible scavenging properties toward hydroxyl radical by suppressing the MB degradation in the reaction media, thus, suggesting that, the MB degradation mechanism proceeds via hydroxyl radical species.

Synthesis and Electrochemical Examination of Fe2O3/CeO2 Nanocomposite for Supercapacitor Application

Fe2O3/CeO2 nanocomposite was synthesized by a chemical precipitation method in room temperature. The prepared nanocomposite has been subjected to some characterization techniques such as XRD, SEM, FTIR, CV, etc., The presence of crystalline phases of CeO2 and Fe2O3 were confirmed by the powder X–Ray diffraction analysis. Surface morphology of the prepared nanocomposite has been analyzed using SEM analysis. The functional group vibrations were analyzed by FTIR technique. The maximum specific capacitance achieved by using 1M KOH electrolyte solution is about 242 Fg-1 at 5 Ag-1 current density.