| dc.description.abstract | Depleting fossil fuels, increasing environmental concerned and looming energy crisis
motivates researcher around the globe to explore some of the possible eco-friendly energy
alternative resources. Among various available selections, electrochemical energy conversion
and storage devices have the potential to serve the portable electronics to automobile sectors.
In this regard, direct alkaline methanol fuel cell (DAMFC) is very promising. The efficiency
of DAMFC mainly depends upon methanol oxidation reaction (MOR) and oxygen reduction
reaction (ORR) that take place at anode and cathode of the device, respectively. However, both
the reactions are complex and sluggish in nature due to multiple electron transfer involvement
and various intermediate species formation during the course of reactions and require catalysts
to drive these reactions at desire rates. Pt is known as the best mono metallic catalysts for both
MOR and ORR, however, it suffers from catalytic poising and various degradation pathways
like dissolution, leaching, agglomeration, Ostwald ripening, etc. Therefore, it is of enormous
importance to enhance the operational stability of Pt based electro catalysts by alloying it with
other available system or to design Pt-free electrocatalysts without trading off between the
activity and stability. Metal-air battery is an energy storage device, relies on ORR and oxygen
evolution reaction (OER) which requires efficient and robust electrocatalysts. The literature
survey suggests that the combined over-potentials of ORR and OER cause a loss of ~ 70 % in
the efficiency of metal-air batteries. Moreover, the commercially available state-of-the-art
electro catalysts like Pt-C (for ORR) and RuO2/IrO2 (for OER), in addition to their high cost,
are known for their mono-functionality only, and so metal-air battery system requires two kind
of electrocatalysts to perform ORR/OER during discharging/charging. Therefore, it is of immense importance to develop commercially viable, robust and bifunctional electrocatalysts
to serve the metal-air battery system. The present thesis presents the rational designing of
bifunctional, robust and commercially viable electrocatalysts for electrochemical energy
conversion and storage devices like DAMFC, metal-air batteries, water electrolyser and their
practical realizations. | en_US |
