Subir Paul

Characterization of Bioelectrochemical Fuel Cell Fabricated With Agriculture Wastes and Surface Modified Electrode Materials

A Bioelectrochemical fuel cell was fabricated with pretreated and fermented rice husks. The fuel was characterized with variation of process variables by determination of chemical oxygen demand (COD) which is a measure of the oxygen equivalent of electrochemically oxidizable organic fuel to produce electrical energy. The electrodes of the cell were made with nano porous anodized Al coated with Platinum, Platinum-Ruthenium and Platinum-Ruthenium-Carbon. Anodization parameters were optimized by studying E-I characteristics in sulphuric and oxalic acids with variation of concentration and temperature. Pore size in the order of 30–50 nm was obtained by a two stage anodization. The performance of the cell was evaluated by determining open circuit potential, E-I characteristics, polarization studies and cyclic voltammetry. A steady onload potential of 600–800 mV was obtained with current density in the order of 15–25 mA/cm2 . High power density of 10–15 mW/cm2 has been obtained with electrode materials coated with Pt+Ru or Pt+Ru+C. The performance of coating on nanoporous structure was much reflected in the polarization studies, which showed a huge reduction of polarization resistance and increase of exchange current density by many times, the effect being more for anode in anodic solution, fermented rice husk, than with cathode in phosphate buffer cathodic solution. The surface morphology examined by SEM, showed nano deposits of Pt, Pt-Ru and the presence of carbon like structure. XRD peaks clearly reveal presence of Pt, Pt-Ru and carbon.Copyright

Electrochemical characterization of Ni-Co and Ni-Co-Fe for oxidation of methyl alcohol fuel with high energetic catalytic surface

Abstract Non Pt based metals and alloys as electrode materials for methyl alcohol fuel cells have been investigated with an aim of finding high electrocatalytic surface property for the faster electrode reactions. Electrodes were fabricated by electrodeposition on pure Al foil, from an electrolyte of Ni, Co, Fe salts. The optimum condition of electrodeposition were found out by a series of experiments, varying the chemistry of the electrolyte, pH value, temperature, current and cell potential. Polarization study of the coated Ni-Co or Ni-Co-Fe alloy on pure Al was found to exhibit high exchange current density, indicating an improved electro catalytic surface with faster charge- discharge reactions at anode and cathode and low overvoltage. Electrochemical impedance studies on coated and uncoated surface clearly showed that the polarization resistance and impedance were decreased by Ni-Co or N-Co-Fe coating. X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX) and atomic absorption spectroscopy (AAS) studies confirmed the presence of alloying elements and constituents of the alloy. The morphology of the deposits from scanning electron microscope (SEM) images indicated that the electrode surface was a three dimensional space which increased the effective surface area for the electrode reactions to take place.

Electrochemical Characterization of Synthesized Ni–Co and Ni–Co–Fe Electrodes for Methanol Fuel Cell

Pt based materials having high electrocatalytic properties are normally used for the electrodes of the fuel cell. But the cost of the material limits the commercialization of alcoholic fuel cell. Non-Pt based metals and alloys as electrode materials for methyl alcohol fuel cells have been investigated with an aim of finding high electrocatalytic surface property for the faster electrode reactions. Electrodes were fabricated by electrodeposition on pure Al foil, from an electrolyte of Ni, Co, and Fe salts. The optimum condition of electrodeposition was found by a series of experiments, varying the chemistry of the electrolyte, pH, temperature, current, and cell potential. Polarization study of the coated Ni–Co or Ni–Co–Fe alloy on pure Al was found to exhibit high exchange current density, indicating an improved electrocatalytic surface with faster charge– discharge reactions at anode and cathode and low overvoltage. Electrochemical impedance studies on the coated and uncoated surface clearly showed that the polarization resistance and impedance were decreased by Ni–Co or N–Co–Fe coating. X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), and atomic absorption spectroscopy (AAS) studies confirmed the presence of alloying elements and constituents of the alloy. The morphology of the deposits from scanning electron microscope (SEM) images indicated that the electrode surface was a three-dimensional space which increased the effective surface area for the electrode reactions to take place. [DOI: 10.1115/1.4029063]

Biocompatibly Coated 304 Stainless Steel as Superior Corrosion-Resistant Implant Material to 316L Steel

Surface treatments of 304 stainless steel by electro-coating and passivating in few inorganic electrolytes were found to be very effective in drastically reducing the corrosion rate of the material in stimulated body fluid (SBF) by several orders in comparison to that of 316L steel, presently being used for orthopedic implants. Polarization studies of electrodeposited hydroxyl apatite coating on 304 steel showed remarkably improved corrosion current. Cyclic polarization of the material in SBF reflected the broadened passivity region, much lower passive current, and narrower hysteresis loops. Similar effects were also found through the formation of inorganic coatings by passivation in NaF, CaNO3, and calcium phosphate buffer solutions. Surface characterization by XRD showed the peaks of the respective coating crystals. The morphology of the coatings studied by SEM showed a flake-type structure for hydroxyapatite coating and fine spherical-subspherical particles for other coatings.

Synthesis and characterization of ZnO-Al2O3 oxides as energetic electro-catalytic material for glucose fuel cell

Abstract One of the thrust areas of research is to find an alternative fuel to meet the increasing demand for energy. Glucose is a good source of alternative fuel for clean energy and is easily available in abundance from both naturally occurring plants and industrial processes. Electrochemical oxidation of glucose in fuel cell requires high electro-catalytic surface of the electrode to produce the clean electrical energy with minimum energy losses in the cell. Pt and Pt based alloys exhibit high electro-catalytic properties but they are expensive. For energy synthesis at economically cheap price, non Pt based inexpensive high electro catalytic material is required. Electro synthesized ZnO-Al2O3 composite is found to exhibit high electro-catalytic properties for glucose oxidation. The Cyclic Voltammetry and Chronoamperometry curves reflect that the material is very much comparable to Pt as far as the maximum current and the steady state current delivered from the glucose oxidation are concerned. XRD image confirms the mixed oxide composite. SEM images morphology show increased 3D surface areas at higher magnification. This attributed high current delivered from electrochemical oxidation of glucose on this electrode surface.

Corrosion Behavior of Carbon Steel in Synthetically Produced Oil Field Seawater

The life of offshore steel structure in the oil production units is decided by the huge corrosive degradation due to , S2−, and Cl−, which normally present in the oil field seawater. Variation in pH and temperature further adds to the rate of degradation on steel. Corrosion behavior of mild steel is investigated through polarization, EIS, XRD, and optical and SEM microscopy. The effect of all 3 species is huge material degradation with FeSx and FeCl3 and their complex as corrosion products. EIS data match the model of Randle circuit with Warburg resistance. Addition of more corrosion species decreases impedance and increases capacitance values of the Randle circuit at the interface. The attack is found to be at the grain boundary as well as grain body with very prominent sulphide corrosion crack.

Electrochemical characterization of MnO2 as electrocatalytic energy material for fuel cell electrode

Abstract Development of Inexpensive non Pt based high electrocatalytic energy materials is the need of the hour for fuel cell electrode to produce clean alternative green energy from synthesized bio alcohol using Biomass. MnO 2 , electro synthesized at different current density is found to be well performed electrocatalytic material, comparable to Pt, with higher current density, very low overvoltage for the electrochemical oxidation of methanol. From EIS study, the polarization resistance of the coated MnO 2 is found to be much low and electrical double layer capacitance is high, the effect increases with increase in current density of electro deposition. XRD, EDX and AAS analysis confirm the MnO 2 deposition. The morphology of SEM images exhibits an enhanced 3D effective substrate area, for electro oxidation of the fuel. A few nano structured grains of the deposited MnO 2 is also observed at higher current density. The fact supports that a high energetic inexpensive electro catalytic material has been found for fuel cell electrode to synthesis renewable energy from methanol fuel.

Prediction and Computation of Corrosion Rates of A36 Mild Steel in Oilfield Seawater

The parameters which primarily control the corrosion rate and life of steel structures are several and they vary across the different ocean and seawater as well as along the depth. While the effect of single parameter on corrosion behavior is known, the conjoint effects of multiple parameters and the interrelationship among the variables are complex. Millions sets of experiments are required to understand the mechanism of corrosion failure. Statistical modeling such as ANN is one solution that can reduce the number of experimentation. ANN model was developed using 170 sets of experimental data of A35 mild steel in simulated seawater, varying the corrosion influencing parameters SO42−, Cl−, HCO3−,CO32−, CO2, O2, pH and temperature as input and the corrosion current as output. About 60% of experimental data were used to train the model, 20% for testing and 20% for validation. The model was developed by programming in Matlab. 80% of the validated data could predict the corrosion rate correctly. Corrosion rates predicted by the ANN model are displayed in 3D graphics which show many interesting phenomenon of the conjoint effects of multiple variables that might throw new ideas of mitigation of corrosion by simply modifying the chemistry of the constituents. The model could predict the corrosion rates of some real systems.

Development of Ni-Cu and Ni-Cu-CeO 2 as high energetic material to electro-oxidization of glucose to produce clean renewable energy

Utilization of energy has been rapidly enhanced with our civilization. As a result of fact, huge amount of fossil fuels are used to execute this energy which creates a lot of environmental pollution. New technology of producing energy through alternative route is the need of the hour. One of the major research areas to produces clean energy by electrochemical oxidation of renewable fuel, such as glucose, in fuel cell. Electrochemical oxidation of fuel requires high electro-catalytic surface of the electrode to produce the clean electrical energy with minimum energy loss. Pt and Pt base materials are considered as very superior electro-catalysts but they are costly. Development of non Pt based inexpensive high electro catalytic materials can lead to producing energy at economically viable rate. In this present investigation Ni-Cu and Ni-Cu-CeO2 electrode material were electro synthesized by pulse current. The developed materials were electrochemically characterized by Cyclic Voltammetry (CV), Chronoamperometry (CA) and Potentiodynamic polarization test. It is interesting to find that both these materials have shown very comparable electro catalytic properties in terms of high exchange current density (I0), low polarization resistance (Rp), and delivers very high current compared to Pt. The surface morphology of the electro materials structure has been revealed by SEM, FESEM. It is seen that grains are narrow and sub spherical with 3D surface containing vacancy in between two elongated grains. XRD study exhibits the presence of Ni and CeO2 on the Cu surface.

Materials and Electrochemistry: Present and Future Battery

Though battery chemistry and technology had been developed for over a hundred years back, increase in demand for storage energy, in the computer accessories, cell phones, automobile industries for future battery car and uninterrupted power supply, has made, the development of existing and new battery, as an emerging areas of research. With innovation of high energetic inexpensive Nano structure materials, a more energy efficient battery with lower cost can be competitive with the present primary and rechargeable batteries. Materials electrochemistry of electrode materials, their synthesis and testing have been explained in the present paper to find new high efficient battery materials. The paper discusses fundamental of electrochemistry in finding true cell potential, overvoltages, current, specific energy of various combinations of anode-cathode system. It also describes of finding the performance of new electrode materials by various experiments viz. i. Cyclic Voltammetry ii. Chronoamperometry iii. Potentiodynamic Polarization iv. Electrochemical Impedance Spectroscopy (EIS). Research works of different battery materials scientists are discussed for the development of existing battery materials and new nano materials for high energetic electrodes. Problems and prospects of a few promising future batteries are explained.