Microwave synthesis of NiMn2O4/Ni-foam: Efficient bifunctional electrocatalysts for overall water splitting

The development of efficient and earth-abundant electrocatalysts for water splitting is necessary and crucial. In this study, NiMn2O4 nanosheets and nanosphericals were grown on Ni foam by microwave synthesis at 150 °C and 175 °C and the corresponding synthesized materials were referred to as NIM-150 and NIM-175, respectively. These materials were subsequently used as bifunctional electrocatalysts for the oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and overall water splitting. The NIM-175 electrocatalyst showed a lower overpotential of 250 mV for the OER and 248 mV for the HER at 10 mA cm−2, and a smaller Tafel slope of 218 mV dec−1 for the OER and 198 mV dec−1 for the HER, compared to NIM-150. The NIM-150 and NIM-175 electrocatalysts exhibited excellent stability for overall water splitting.