M.S. Hegde

Solid State Chemistry and Catalysis, Electron Spectroscopy and Surface Science

Our research interest is broadly in the area of synthesis, structure and properties of new oxide materials, transition metal nitrides, epitaxial oxide films by pulsed laser deposition for electronic and ionic transport and heterogeneous catalysis. Study of electronic structure of solids and surfaces by X-ray photoelectron spectroscopy and their theoretical understanding by Density Functional Theory (DFT) calculations are our main research interests. Recently, we have pursued synthesis of nanocrystalline oxide materials by a novel solution combustion method. Substitution of noble metal ions in reducible oxides such as CeO2, TiO2, SnO2 and their derivatives are shown to be the best auto exhaust catalysts for CO and hydrocarbon oxidation and NO reduction. Solid solutions of the type Ce1-xMxO2-δ (noble metal, M = Pt, Pd, Rh, Ru, Cu, Ag, Au) made by solution combustion method showed orders of magnitude higher catalytic activity compared to the corresponding metal nano-crystallites  for a number of catalytic reactions such as hydrogen generation by water gas shift reaction, hydrogen-oxygen recombination, auto exhaust catalysis. The idea of noble metal ions associated with oxide ion vacancy as active sites for reducing and oxidizing molecules in these ionic catalysts  against only the metal atoms in metal nano particles  has opened up new ways to generate novel redox catalysts hitherto unknown in the literature.