Palladium-nitrogen coordinated cobalt alloy towards hydrogen oxidation and oxygen reduction reactions with high catalytic activity in renewable energy generations of proton exchange membrane fuel cell

Oxygen reduction reaction (ORR) is one of the most important processes in energy conversion and conservation in proton exchange membrane fuel cell (PEMFC). In PEMFC, developing non-platinum based catalyst by understanding the catalytic activity for both oxygen reduction reaction (ORR) and hydrogen oxidation reaction (HOR) is essential for energy storage/conversion. Herein, we report preparation of such a bi-functional and durable catalyst consists of palladium and nitrogen coordinated cobalt and its catalytic activity is discussed methodically. Palladium cobalt bimetallic alloy nanoparticles dispersed over graphitic carbon nitride (Pd-Co/gCN) serves as an efficient anode and cathode catalyst in proton exchange membrane fuel cell for energy conversion. Incorporation of cobalt with palladium in nitrogen rich support material optimally modifies the bond strength of palladium-hydrogen (Pd-H) complex and promotes HOR, results in significant improvement of overpotential at the anode whereas, the nitrogen coordinated cobalt predominantly enhances the ORR activity at the cathode in acidic medium. Effects of mass transfer on the kinetics of ORR were investigated with rotating disc electrode (RDE). The hydrodynamic voltammograms were investigated to determine the kinetic parameters using the Koutecky-Levich equation. Our study presents an experimental realization of unveiling a good power density with high fuel utilization efficiency in a single cell for electrochemical energy conversion with complete elimination of platinum.