Current Research (PostDoc)

 

One objective of my research is focused on synthesis, characterization, and catalytic activity of nanoparticle catalysts on pore-expanded MCM-41. The other objective is the design of novel adsorbents for effective CO2 capture from the environment using ionic liquids.

PhD Research

 

My research was focused on two objectives; the study of structured nanoparticles in ionic liquid solvents, and rationally synthesizing heterogeneous catalysts from structured nanoparticle precursors.

Focusing on the first objective, I studied the catalytic activity of metallic and bimetallic nanoparticles in imidazolium ionic liquids. Ionic liquids (ILs) have recently emerged as an intriguing reaction media for “quasi-homogeneous” solution-phase nanoparticle catalysis due to the unique properties of ILs, such as high polarity, negligible vapor pressure, high ionic conductivity, and excellent thermal stability, and the fact that the driving forces for nanoparticle aggregation have been reported to be much lower in IL solvents. I have found that the room temperature imidazolium-based ionic liquids are effective media for the direct synthesis of Au, Pd and bimetallic PdAu nanoparticle synthesis, and that the resulting nanoparticles are effective and selective quasi-homogeneous catalysts towards a wide-range of hydrogenation and oxidation reactions. I have investigated the recyclability, reuse, mode-of-stability, and long-term stability of these ionic-liquid supported nanoparticle catalysts; all of which are important factors in determining the overall “greenness” of such synthetic routes.

This work has been published in different journals like J. Mol. Catal. A: Chemical, 2008, 286, 114, MRS Symp. Proc., 2008, 1082-Q04-02, Chem. Comm., 2009, 812, and J. Mol. Catal. A: Chemical, 2010, 329, 86.

The field of heterogeneous catalysis has long recognized the advantages of using nanostructured materials in order to take advantage of their large surface area and resulting high catalytic activities. My second objective was focused on synthesizing the well-structured and well-defined supported catalysts by incorporating the nanoparticle precursors (Au, Pd, and AuPd) into the mesoporous oxide frame works (TiO2, Al2O3), and studying their catalytic activity.

Initially, the synthesis of co-reduced and core-shell Pd-Au nanoparticles stabilized by poly(vinylpyrrolidone) (PVP) have been carried out and found that they can be captured in oxide gels, followed by careful calcination of the polymer stabilizer to give PdAu nanoparticles dispersed throughout mesoporous alumina materials. Detailed characterization of these materials via HRTEM, energy dispersive spectroscopy (EDS) and extended x-ray absorption fine structure (EXAFS) spectroscopy and x-ray absorption near edge spectroscopy (XANES) has shown that the co-reduced nanoparticles have approximate alloy structures whereas sequentially reduced nanoparticles have Pd-Au core-shell structures. Calcination and reduction of the particles at mild temperatures (300 degree C) allowed for retention of the nanoparticle compositions, size and structures along with the activation of the particles for catalysis, while calcinations at higher temperatures led to rapid nanoparticle sintering and loss of compositional control of the final nanoparticles.

This work has been published in journals like J. Phys. Chem. C, 2009, 113 (29), 12719 and MRS Symp. Proc., 2010, 1217-Y01-07.

Finally, I worked on routes which use ionic liquids as one-pot media for the synthesis of highly porous supported-nanoparticle heterogeneous catalysts via the trapping of pre-synthesized nanoparticles into porous inorganic oxide material. This work has been published in Mater. Lett., 2011, 65, 07.

M.Tech Research

The objective of my project was the synthesis and characterization of Bioactive Composite materials and their Bioactivity and Mechanical studies. Bioactive ceramic powders were synthesized by chemical solution technique (sol–gel route). Polymers like PMMA, Epoxy resins were used for the production of composites. Trans PMAI, 2004, 30, 01