Terpyridine Based Self-assembly of Nanoparticles – Application in Direct Methanol Fuel Cell: On catalysis front we use nanomaterials for oxidation methanol, ethanol etc. Polypridine functionalized platinum and ruthenium nanoparticles are self-assembled on a electrode in such a way that Pt and Ru nanoparticles are self-assembled alternatively. The performance of the electrode consisting of above nanoparticles assembly are evaluated for methanol oxidation. The schematic given below clearly depicts the idea explained
Chemically modified semiconductor electrodes (CMSEs): “Enzyme-like” (Non-enzymatic) approach for sensing applications: Also the group works on developing sensors and catalytic materials for alcohols and sugars by monitoring their corresponding direct electrochemical oxidation processes using chemically modified semiconductor electrodes. Basically, the target (analyte) binding redox moieties immobilized on semiconductor electrodes result in non-enzymatic detection of sugars and alcohols. Addressing the fundamental issues related with electron transport across semiconductor electrode – electrolyte interface and creating enzyme-like behaviour without the use of enzymes are some of the key features of this project. A simple, cost-effective but efficient and reliable methodology is developed for chemical modification of semiconductor electrodes (Refer to Schemes 1&2).
Scheme 1: Pictorial representation of the strategy adapted for chemical modification of ITO electrodes to design and fabricate electrocatalysts for direct alcohol oxidation process.
Scheme 2: Schematic representation of the methodology followed to design and develop a novel platform for direct electrocatalytic oxidation of carbohydrates in alkaline medium.
Exploring modified semiconductor electrodes as sensors and catalysts: Self-assembled monolayer films of various molecules on metallic surfaces such as Au, Ag and Cu are well explored, while the monolayer studies on semiconductor electrodes are fairly limited. Semiconductor electrodes such as ITO, silica (SiO2) and TiO2 have interesting physical and chemical properties like optical transparency, semi-conducting behaviour, chemical stability and high surface area. These electrodes are proposed to be modified with self-assembled monolayer films. Molecules having different structural components (as shown in scheme 3) such as substrate binding (SB) domain, spacer (electron transport) region (SR) and terminal functionality (TF) will be utilized for SAM formation. These functionalities will further be exploited for enzyme (EZ) immobilization. Several well-known interactions viz. electrostatic, hydrophobic, covalent bonding and anchoring of nanoparticles will be explored for enzyme immobilization and its activity on these modified surfaces is to be investigated. The present work is to establish the methodology and to understand the mechanism of action on silane modified semiconductor electrodes. We propose to form a stable and ordered monolayer films on these electrodes using amine, carboxyl and thiolate terminated alkylsiloxane compounds. These modified electrodes will be used later to immobilize the biologically active molecules (enzymes). Several important reactions such as oxygen reduction, hydrogen peroxide reduction, glucose oxidation and ethanol oxidation will be performed using enzymes incorporated semiconductor electrodes. It could also be mentioned that these transparent metal oxide platforms can also be used for optical sensing, although this is not a part of proposed work.
Scheme 3: Pictorial representation of the proposed methodology for systematic modification of semiconductor electrodes to develop sensors and catalysts.