The main focus of our research is to understand interfacial properties involving novel materials and modified surfaces. Our present attention is focused on the following classes of materials. We use a combination of spectroscopy, electrochemistry and microscopy techniques. Coupled in-situ techniques based on electrochemical FTIR, Raman electrochemistry are routinely used to understand various aspects.
Transition metal nitrides, carbides and chalcogenides:
Towards exploring new electrode materials, we have been working on titanium nitride, titanium carbide, and carbonitride- based electrodes. The nitrides and carbides show exceptional stability and good electronic conductivity combined with the ability to support catalyst particles. * Transition metal chalcogenides, particularly layered sulphides and selenides are amenable for preparing few layer materials that possess interesting electrical and electrochemical properties. Our current interest is to prepare well- defined single layer/few layer materials of binary and ternary chalcogenides. * We use nitrides, carbides and various chalcogenides for small molecule oxidation, hydrogen evolution (HER), oxygen reduction (ORR) and oxygen evolution reaction (OER) studies. * Many of the nanostructured nitrides, carbides and chalcogenides are also tried as electrode materials for secondary lithium-ion, sodium-ion and magnesium-ion batteries.
Organic thin films (SAMs and LB films):
In the area of organic thin films, our objective is to prepare stable, compact and well-oriented organic thin films consisting of donor-space-acceptor assemblies. Intramolecular electron transfer in constrained thin films and formation of rectification assemblies are pursued. Orientation dependent electrocatalysis using macromolecular thin films is another area of our interest.
Exfoliated graphite, graphene oxide and graphene:
Exfoliated or expanded graphite (EG) is a low dense graphitic carbon with high temperature resistance. The density of the expanded material is very low, of the order of 0.004 g/cm3. The exfoliated graphite particles can be recompressed or re-stacked without any binder. Graphene/ graphene oxide is very thin and consists of a monolayer of carbon/ (oxidized carbon) atoms tightly packed into a two-dimensional honeycomb lattice. It has gained considerable attention due to its extraordinary electronic, thermal and mechanical properties. Our interest is on the assemblies of exfoliated graphite and graphene oxide/ reduced graphene oxide and their studies. * Present focus is on Langmuir and Langmuir-Blodgett films of graphene oxide and graphene oxide-assisted (electro) chemistry at interfaces towards understanding the interfacial properties and to develop new and novel materials. * Direct electron transfer of redox active enzymes modified through graphene oxide assemblies and sensors for detection of low concentration (picomolar) of analytes are also pursued. * Graphene oxide - nanoparticle composites are being used as catalysts for small molecule oxidation. Intercalation in well-defined number of graphene layers is another area of our current interest. * Graphene based materials are studied for electrochemical supercapacitors.
Nanostructured materials:
Research on nano-particles and nanobimetallics has been quite extensive over the last few decades. Our interest is to prepare nanometallic structures based on Os, Ir, and Al etc. Bimetallic and alloy clusters are also prepared and used for electrocatalysis. * Use of different (bi)metallic and other nanostructures as substrates for surface enhanced Raman scattering (SERS) studies is one of the main areas of interest.
Deep Eutectics- Molten electrolytes:
Studies on deep eutectic molten liquids/electrolytes for electrodeposition as well as the preparation of nanostructures are pursued with amide-based solvents. The room temperature deep eutectics are good ionic conductors and are useful as electrolytes in batteries as well. Molten electrolytes with magnesium, zinc and lithium ion conductivity are prepared and studied for secondary batteries.
Organic electrode materials:
We have recently initiated work on naturally occurring / synthetic organic electrode materials for secondary batteries. Ellagic acid, a polyphenol extracted from pomogranate has been recently shown to be a good cathode material for rechargeable lithium batteries. Other quinone and phthalocyanine based materials are being looked at, as possible candidates, for batteries.