Doctoral & Post Doctoral Work

         Seven years of Post Doctoral Research, one year of Research Associate and six years of Doctoral Research experience in the inter-disciplinary areas of Experimental Solid State (Condensed Matter) Physics/Inorganic Chemistry/Chemical Engineering/Material Science Engineering and Nanotechnology. The brief summary of the research works carried out through the post doctoral and doctoral program and significant contributions are given in the following sections.
Post Doctoral work at University of South Florida:      (Feb. 01’04-Till date)
         The current Post Doctoral program at the Clean Energy Research Center, University of South Florida focuses on the three hydrogen economy thrust areas such as hydrogen production, hydrogen storage and hydrogen conversion through fuel cells.
Project 1. Hydrogen production from solar energy is known for quite sometimes. However, for improving the efficiency of hydrogen production through photochemical/photocatalytic process, development of novel semiconductor hetro-junction catalysts seems vital important. Also the photocatalytic activity of these semiconductor oxide materials necessitates research and development of materials synthesis and characterization. Based on these factors,

  • I have developed nano-composite TiO2 (Anatase) sensitized with Cadmium Sulfide. I have adopted a reverse micelles procedure to prepare these photocatalytic materials and tested their photocatalytic activity by phenol degradation measurement in water suspension. Metrology tools such as XRD, SEM-EDS, and UV-Vis have been used to characterize the as-prepared nano-composite quantum CdS sensitized TiO2.
  • I have also successfully designed and developed TiO2/ZnFe2O4 nanocomposite by co-precipitation/hydrolysis process for the visible light photocatalytic degradation of phenol. My work on synergistic effects of sulfation and Zn2+/Fe3+ co-doping on the TiO2 visible light catalysis have been widely cited by many other scientists.
  • Very recently, I have explored the novel thermo chemical treatment of TiO2 and its enhancement in the degradation performance. Right now I am involved in the development of nano composite materials TiO2-ZnFe2O4, nano TiO2, nano TiO2/C, TiO2/N2 by an inexpensive mechanochemical synthesis process employing high energy ball mill. Various experimental parameters such as milling speed, duration, medium etc have been optimized to achieve the nanoparticles with integrity and presently testing their visible light characteristics for the degradation of phenol. The mechanochemistry of reducing the size of the particles thus enhance the visible light photoactivity of the materials by altering their energy band gap.
  • Quantum size effects on the band gap engineering of ZnFe2O4 nanoparticles have been extensively studied by us. The nanoconfinment with grain size of around 10 nm have been achieved by mechano-chemical milling under dry and wet milling condition. The red and blue shift of the optical characteristics were compared and correlated with structural, microstructural and surface properties.
  • Currently we are also in collaboration with Italian Scientists to develop Zn2+ doped TiO2 for photocatalysis applications. The TiO2 samples are prepared in various forms such as nanofibers, nanospheres etc. by chemical sol-gel and electrospun techniques.
  • I have involved in projects related to by-product hydrogen production from H2S and SO2. Various electrodes and catalysts testing have been carried out for the low voltage hydrogen production using electrochemical cell fabricated by our group.
  • The current program on photocatalytic material development for detoxification and hydrogen production is supported by the Center for Biological defense (CBD), NASA and US Department of Energy.        

Project 2.Development of light weight hydrogen storage systems bearing alkali/alkaline (Mg, Na, Li) materials are focused on this current program.

  • The chemical or mechano-chemical formulations of nano scale transition metal complex hydride (n-Mg2FeH6) have been carried out. The kinetics of hydrogenation and dehydrogenation, and the temperature of hydrogen desorption of n-Mg2­FeH6 is improved by incorporating Ti- based catalysts on the host structure. Also the thermodynamic tailoring has been performed by lattice substitution mechanism.
  • Yet another study involves designing nano-composite conducting polymer materials with 6 wt.% hydrogen storage capacity will be developed to meet the US-DOE goals. In collaboration with Italian Scientists, I have performed hydrogen sorption measurements of Polyaniline nanofibers and nanospheres fabricated by chemical and electrospun routes. These materials show good cyclic reversibility up to 3.0 wt.% at room temperature. We are currently under process to establish structure-property relation for these polymer matrices.
  • Recently, I have reported new thermally activated boro-hydride complex system [Zn(BH4)2] and demonstrates the sorption properties at low temperatures of less than 100o C for on-board fuel cell vehicles. The nanocatalyst (up to 10 nm)of transition metal dopants were found to improve the kinetics of reaction and at the same time reduces the evolution of di-borane gas by a factor of 20. I have compared and correlated the hydrogen decomposition of Zn(BH4)2 for hydrogen storage applications. In a similar manner, I have also prepared some of the other complex borohydrides such as Mn(BH4)2, Zn(BH4)4 and Ca(BH4)4. I strongly collaborate with Dr. Jensen’s group of University of Hawaii and working with TPD, DSC/TGA analysis of some of neutral borohydride mixtures such as LiMn(BH4)2, LiSc(BH4)2 and NaMn(BH4)2.
  • I am also developing the Lithium amides and related complex systems for the effective reversible hydrogen storage capacity. Recently we have synthesized new quaternary structure bearing light weight elements Li-B-N-H and destabilized the structure by commercial and nanocrystalline MgH2 for high reversible hydrogen storage capacity. This is yet to be reported for publications. We are also in parallel looking for muli-component complex-composite hydrides for on-board hydrogen storage.
  • Nanocrystalline MgH2 by solid state mechano-chemical processing and effect catalyst doping has been carried out recently. We found superior hydrogen storage capacity, rapid kinetics and properties for the CNT/Transition metal nanoparticle doped hydrides.

I have collaborations with University of Hawaii, University of Florida, University of L’Aquilla, Italy and other partners for the above hydrogen storage projects. These projects are financially supported by the US Department of Energy.

Project 3.For the Fuel cell and hydrogen conversion project, I have been involved in characterization of the solid electrolyte materials (e.g. CsHSO4, BaHPO4, RuO2 thin films on Si Substrate etc.) by differential scanning calorimetry, X-ray diffraction and Scanning Electron Microscopy. Recently, we are preparing nanocomposites of MoS2, CoS2/RuO2 and testing the electrochemical characteristics for the hydrogen evolution. The current research program is supported by the NASA and DOE.
I have been carried out the above said research works in various Engineering departments, Electrical, Mechanical, Chemical engineering and Nanomaterials and Nanomanufacturing center, Clean Energy Research center of University of South Florida. The outcome of the results of these investigations are presented to the scientific community in various peer reviewed journals, book chapters, scientific society meetings such MRS, TMS and AIChE and DOE review meetings.
Project Management/Technical Team Leader: My current duties also involved with overall project management and reporting to the funding agencies. Quarterly and Annual reports will be prepared by me at regular period of time and coordinate all the projects from other PIs and finally report to the agencies. Besides this documentation works, I am also responsible for preparing CERC center annual report and CERC semi-monthly newsletter. CERC website is maintained and updated by me. Lab demonstration, training, maintenance of equipment, proposal writing, functioning and operation will be part of my daily activities currently. Overall, I am taking in charge of Hydrogen Production, Storage and Conversion laboratory of CERC as Technical Team Leader for the on-going center projects.
Post Doctoral work at University of Hawaii:                  (Jan, 01’02-Jan, 31’ 04)
During this Post Doctoral program, I have been involved in designing and developing novel complex hydrides (e.g. NaAlH4) by chemical synthesis and doping procedures. The breakthrough discovery of titanium doped NaAlH4 which led to a high hydrogen storage capacity at moderate temperatures was explored. A mechanistic study related to the role of titanium/zirconium catalysts on the kinetics was identified and determined the enthalpies of activation of the two step decomposition reactions of catalyzed NaAlH4. Re-hydrogenation of dehydrogenated Ti- doped NaAlH4 at low temperatures and pressures were reported for the first time by us. Also, I have investigated and carried out some interesting long term cycling (100 cycles) experiments of Ti- doped NaAlH4, prepared from the elemental mixtures of Ti- doped NaH and Al through unique approach of solvent mediated milling process. With the collaboration of Norway research group and GE Global research, we have investigated the structural and microstructural characteristics of Ti- doped NaAlH4 using synchrotron x-ray diffractometer and imaging techniques. I have successfully manufactured 500 grams of purified NaAlH4 by using soxlet filtration and supplied the sample to the Japan Steel Works (WE-NET collaboration program of Japan) for Research and Development. I have given technical consultation for the procedures to prepare and purify these materials to researchers at Banaras Hindu University, India.
Research Associate & Doctoral work at Banaras Hindu University:        (Jan, 01 ’94-Dec, 31’01)
Seven years of Doctoral research experience in the area of Solid State and Condensed Matter Physics. During the Doctoral program, I have successfully synthesized the intermetallic hydrides of the family, AB5, AB2 Laves Phases, AB, Solid solution alloys, the Mg based alloys namely, Mg2Ni, Mg-xwt.% CFMmNi5, Mg-xwt.% CFMmNi5-ywt.% Si, Mg-xwt.% MmNi4.6Fe0.4, and Mg2FeH6 (K2PtCl6 type) prepared through R.F. Induction melting (conventional) and mechanical alloying (unconventional) processes. The reversible hydrogenation and dehydrogenation characteristics have been correlated with the structural and microstructural observations using XRD, TEM, SEM and EDAX techniques. The Mg2FeH6 phase proportion of 63% obtained from the mechanical alloying process by me was first ever reported highest yield. The as-synthesized composite materials were tested in the hydrogen fuelled IC Engine. My research dissertation was highly appreciated and commended by the expert committee members (Professor T. Nejat Veziroglu, President, International Association for Hydrogen Energy, USA). Indian local newspapers published news columns of the research work of converting H2 fueled IC engine for automotive applications, in which I have made some major contributions. Besides, I have initiated an international collaboration on the Hydrogen Storage project with Ukrainian scientists and it was funded by the Ministries of both the Indian and Ukrainian Governments.