Hydrogen Oxygen Fuel Cell and Energy Storage by Carbon Nano-Materials
Chatterjee Arup Kumar , Ph.D, 04
Supervisor(s): Rangan Banerjee
Fuel cell is an efficient and environment friendly energy conversion device. For practical application of fuel cell (Hydrogen-Oxygen), it is important to have suitable hydrogen storage materials and an auxiliary power device (super capacitor). The major constraint associated with this device is its high cost. This research explores the use of carbon nanomaterials as a solution for fuel cell, super capacitor and materials for hydrogen storage. In this research work, hydrogen-oxygen fuel cell was indigenously developed using low cost materials. Novel porous ceramic was used as electrode substrate. Different forms of carbon nanomaterials (beads, fibers and nanotubes) were synthesized by Chemical Vapor Deposition method using turpentine oil - a low cost natural precursor. These nanomaterials were used as support for electrocatalysts. Different monometallic/bi-metallic/alloy catalysts were used for hydrogen oxidation (Pt, Pd, Ni, Co, Fe, and Sn) and oxygen reduction (Ag, Pt, Pd, Mn, Mg, Ni, Co, Al, Cu, Ce, and Fe). Some oxygen active ternary catalysts (Ag, Fe, Co, Cu and Ce) prepared by urea decomposition method were used both as electrocatalysts and as catalysts for the growth of nanotubes. Carbon nanomaterials were also synthesized to store electrochemical energy (Double Layer Super Capacitors) as well as Hydrogen energy from turpentine oil and agricultural waste (cane plant waste and betel nut shells). Different acid and alkali treatments were done to purify and activate the carbon nanomaterials. These carbon nanomaterials were studied both before and after activation. In order to study the surface morphology and the elemental composition of the different carbon materials, SEM, TEM, XRD and XRF analysis were done. To measure the conductivity of the electrodes, variation of resistance with respect to temperature was recorded by Vander-Pauw Resistivity method. The electrochemical performance of the electrodes for Fuel Cell was investigated by measuring the Hydrogen dissociation voltage, Half-cell and Full cell I-E and Chronoamperometry characteristics. For super capacitor, the capacitance measurements of the carbon nano materials were done by Cyclic Voltammetry and Galvanostatic charging-discharging experiments. Hydrogen adsorption studies were done by physical adsorption, Raman, TGA/DTA and CHNO analysis. Amongst different carbon nanomaterials, CNT was found to be best electrode material for Alkaline Fuel Cell (AFC). The voltages obtained were 96.5\% and 98.2% of theoretical hydrogen and oxygen dissociation voltages. The results obtained from the research shows that Ni-Sn (85:15) is an efficient hydrogen electrodes and Ag-Mg (70:30), Ag-Fe-Cu (83:13:4) are best as oxygen electrode. The maximum current density of 384 mA/cm2 and maximum power of 262.3 mW/cm2 were recorded with these electrodes. A capacitance of 217.7F/g was recorded for carbon nanomaterials obtained from cane plant waste. Hydrogen adsorption studies were done on metal (hydrogen active) intercalated CNT and metal dispersed carbon nanomaterials. Hydrogen adsorptivity of 11.95% and desorptivity of 4.83% were obtained for Pd-Sn dispersed carbon nanomaterial obtained from cane plant waste. The research demonstrates that carbon based nanomaterials can be used as a cost effective solution for fuel cell, super capacitor and hydrogen storage.