Hydrated FePO4 nanoparticles supported on P-doped RGO show enhanced ORR activity compared to their dehydrated form in an alkaline medium

Abstract

One-step hydrothermal growth of FePO₄ nanoparticles (15–25 nm) uniformly decorated on the P-doped reduced graphene oxide (PRGO) was studied for oxygen reduction reaction (ORR) activity. The role of lattice water in the enhancement of catalytic activity in the hydrated FePO₄·2H₂O with respect to its dehydrated form in the alkaline medium was contested. The hydrodynamic LSV at 1600 rpm in alkaline medium (0.1 M KOH electrolyte) indicates an increase in the cathodic current density of the PRGO supported FePO₄·2H₂O catalyst, which reaches as high as 5.8 mA cm⁻², close to the best known commercially available Pt/C catalyst. The stability in terms of retention of activity after 22 000 s with the hydrated form was found to be 90.7% which is 26.7% higher than that of the dehydrated form.