Name of the center: Center of Excellence on Surface Science (CoE-SS)
Coordinators: Dr. C. S. Gopinath, Sr. Principal Scientist, Catalysis Division
Participants: Dr. C. P. Vinod, Dr. C. V. Satyanarayana, Dr. Nandini Devi, Dr. M. V. Badiger, Dr. Mayadevi, Dr. M. Sashidhar, Dr. K. Krishnamoorthy, Dr. K. Sreekumar, Dr. Pankaj Poddar, Dr. Manjusha Shelke
About the Center: Many materials involved in energy and environment related research require an understanding of how molecules interact with surfaces and interfaces or how surfaces and interfaces respond to external stimuli. Surface spectroscopy measurements on materials can possibly aid in developing active or better quality materials. Center of Excellence on Surface Science is catered to contribute in that direction, dealing with material characterization under realistic (working) conditions, such as high temperature and/or pressure, particulate (real-world) materials. Ideal surface science instruments operate under high vacuum, whereas many applications of materials (such as, catalysis) are at atmospheric pressure (or even at high pressure). Large pressure-gap exists between measurement and application conditions. Thus a special emphasis will be placed on relevant spectral analysis under the real-world working (Operando or In-situ) conditions of the materials, or close to that. This is the critical research area and even at global level it is not addressed sufficiently.
The main topic that will be addressed is the nature of surfaces and interfaces and how they behave under reaction or measurement conditions. Indeed this is the common thread that connects various projects being carried out under the CoE SS.
Surface sensitive spectroscopy under working condition of material, such as catalysis reaction will be carried out under working conditions of catalyst and simultaneous measurements will be made, would enable designing materials with improved activity and new materials. Establishment of CoE-SS with major surface science equipments and setup facility for in-situ reactions with all necessary tools to carry out the proposed project work.
A dedicated custom built laboratory ambient pressure photoelectron spectrometer (Lab-APPES), where in-situ measurement at pressures ranging from ultra high vacuum (10-11 torr) to 1 mbar at temperatures ranging from 77 to 873 K is developed (see publication 1 for details) (Lab-APPES photograph shown at the bottom).
Catalytically active Cu, Ag and Au metal and their interaction with molecular oxygen has been studied. A systematic oxidation from Cu-metal to CuO has been thoroughly studied by Lab-APPES.
Electron filling in partially-filled HOMO orbitals and change in its energy in polymer photovoltaic materials has been studied.
With the present Lab-APPES, valence band studies can be carried out at high pressures due to the special design features.
Surface science techniques to understand the materials and processes involved in energy, fuel and environmental related issues. Water-gas shift reaction, Fischer-Tropsch synthesis of alkanes/oxygenates, Fuel-cell catalysis, Surface modification and its influence in catalysis, catalyst deactivation mechanism and interfacial interactions of different phases for organic synthesis.
Surface modification of nanostructures by micro/nanopatterned self assemblies with organic functionalities for chemical and biosensing; surface patterning by scanning electrochemical microscopy for chips and sensors.
Surface modification of hydrogel membranes for applications, such as contact lenses; biofilm and antimicrobial activity correlation.
Microscopy + Spectroscopy to be made simultaneously with AFM-Raman under working condition of materials (to be installed soon).
Publications and Patents:
1. Kanak Roy, C. P. Vinod, C. S. Gopinath, Design and Performance Aspects of a Custom Built Ambient Pressure Photoelectron Spectrometer Towards Bridging the Pressure Gap: Oxidation of Cu, Ag and Au Surfaces at 1 mbar O2 pressure, J. Phys. Chem. C 117 (2013) 4717.
2. S. Nagarajan, K. Thirunavukkarasu, C.S. Gopinath, Possible deNOx management under net oxidizing conditions - A Molecular Beam Study of 15NO+CO+O2 Reaction on Pd(111) Surfaces J. Phys. Chem. C Vol. 115, 21299-21310 (2011).
3. K. Sivaranjani and C.S. Gopinath, Porosity driven photocatalytic activity of wormhole mesoporous TiO2-xNx in direct sunlight, J. Mater. Chem. Vol. 21, 2639-47 (2011).
Photograph of recently installed Lab-APPES at NCL, Pune as a part of CoE-SS