Fe-doped MnO2/NiCo2O4 as Bifunctional Electrocatalyst for Oxygen Evolution Reaction and Oxygen Reduction Reaction in Alkaline Electrolyte

The catalytic performance of spinel oxide NiCo2O4 for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) was investigated. It shows that NiCo2O4 synthesized via hydrothermal treatment at 90 degree celsius followed by calcination at 350 degree celsius exhibits excellent catalytic activity. Furthermore, Fe-doped MnO2 (marked as Fe-M) was introduced as a modifier to further improve the performance of NiCo2O4. As expected, the 20% Fe-M hybrid catalyst (NiCo2O4 modified with 20 wt% Fe-M) displays the best ORR and OER catalytic activity. This is evidenced by its high OER current density of 265 mA cm(-2), high ORR current density of 220 mA cm(-2), low OER Tafel slope of 119 mV dec(-1), low ORR Tafel slope of 167 mV dec(-1). These exceptional results can be attributed to the synergistic effect between NiCo2O4 and Fe-M.