Dr. Jagadeesh Babu VELURU
My current research intersts are but not limited to Electrospun Nanofibers, Eneergy & environmental applications, Natural Gas Hydrates as energy storing options for the future.
Current research Background:
Electrospun nanofibers (ENFs): Electrospinning was employed to produce nanofibers (dia:10 to 100 mm) with polymers (P), metal oxides (MOs) and composites (P-MOs). In general, conducting polymers (CPs) were composited with suitable polymers to produce P-CP nanofibers. The experimental conductivity (AC and DC) measurement was performed on ENFs of P-CP and shown up to quite remarkable improvement. For example, even at lower doping level of CP in P, the Microwave Hall mobility ~17 cm2.V-1s-1 was quite significant. These ENFs produced with P-MOs and followed by selective removal of polymer via calcination result one-dimensional (1-D) porous nanostructures that were used as sensitizer/catalyst for light induced redox process to degrade the toxic and hazardous compounds. The reduction and oxidation processes via watersplitting was also performed under UV and visible illuminations. It is worth noting that by the use of suitable 1-D ENFs structures can trap photons more effectively with the appropriate geometrical configuration during the generation of excitons (e-/h+). The overall dimensions of the nanostructures were similar to the carrier diffusion lengths to facilitate the collection of free charge carriers in the exciton separation process. The effective exciton generation and charge separation resulted in increasing energy conversion efficiency. Therefore, ENFs with high specific surface area facilitate the effective absorption of emitted light, it was potentially used in photocatalytic energy conversion especially with MOs (TiO2, SnO2, ZnO and so on) and incorporation of ionic (Nitrogen, CNTs, Graphene and etc.) species in to the MOs.
Natural gas hydrates (NGH): NGH are non-stoichiometric ice-like crystalline compounds in which gaseous guest (hydrocarbons, CO2, Hydrogen and so on) molecules were trapped in a host lattice formed by water molecules. NGH formation takes place at specific thermodynamically favorable conditions (high pressures >6 MPa and low temperatures 2-5 °C). During the formation of NGH, the cages (cavity that accommodate the guest molecules) forms different crystalline structures (structure-I, structure-II and structure-H) depending on cage dimension and occupancy. For instance, sI type structure show the average cavity radius of small cage and large cage at 0.395 and 0.433 nm, respectively, which is enough to host one methane molecule (0.199 nm) per cage, resulting in a nominal stoichiometry 1CH4. 5.75 H2O. NGH have many potential applications such as natural gas (NG) storage/transportation, H2 storage, CO2 capture/sequestration, and desalination. In our experimental studies, the formation kinetics, mechanism and cage occupancy while NGH formation was observed by coupling macroscopic and microscopic tools. We have demonstrated the thermogram recorded during the high pressure micro differential scanning calorimetry (HP m-DSC) experiment under the methane pressure. It was composed of three steps like cooling, isotherm and warming up. The dissociation enthalpy (DHd) and the dissociation equilibrium temperature of the methane gas hydrates was also identified using HP m-DSC. I do have expertise operating in Raman spectroscopy, the gas consumption/ uptake measurements being performed by using real time measurements (in-situ Raman spectroscopy). This study is expected to get the information about the behavior of both host and guest molecules with respect to the formation and occupancy of cages during the early stage of hydrate formation. In addition, we do identify the hydrate structure formation, phase transformation and kinetics by using real time experiments.