Nickel-Doped Manganese Dioxide Electrocatalysts with MXene Surface Decoration for Oxygen Evolution Reaction

Electrochemical water splitting (EWS) has been considered as an ideal strategy to produce renewable hydrogen energy. However, the application of EWS is hindered by its sluggish kinetics of oxygen evolution half-reaction. In this work, we successfully prepared an efficient MXene-Ni0.075Mn0.925O2/CC catalyst for oxygen evolution reaction (OER) enhanced by a novel electrodeposition process. By corroborating from characterization results, the Ni element has been successfully doped into the MnO2 crystal. In addition, electron microscopy images visualized that MXene firmly cooperated with the Ni-doped MnO2. With the proper amount of Ni doping in the pristine MnO2, more defects were induced. In addition, the two-dimensional (2D) MXene cooperation collaboratively provided more mass transport channels for OER. Therefore, the prepared MXene-Ni0.075Mn0.925O2/CC catalyst exhibited an outstanding catalytic performance with an overpotential of ∼410 mV at a constant current density of 50 mA cm–2, about 105 mV smaller than that of the pristine MnO2/CC catalyst. The proposed electrodeposition method may pave the way for future designing of binder-free electrocatalytic materials for EWS.