Promising Electrocatalytic Water and Methanol Oxidation Reaction Activity by Nickel Doped Hematite/Surface Oxidized Carbon Nanotubes Composite Structures

Tailoring the precise construction of non-precious metals and carbon-based heterogeneous catalysts for electrochemical oxygen evolution reaction (OER) and methanol oxidation reaction (MOR) is crucial for energy conversion applications. Herein, this work reports the composite of Ni doped Fe₂O₃ (Ni−Fe₂O₃) with mildly oxidized multi-walled CNT (O−CNT) as an outstanding Mott-Schottky catalyst for OER and MOR. O−CNT acts as a co-catalyst which effectively regulates the charge transfer in Ni−Fe₂O₃ and thus enhances the electrocatalytic performance. Ni−Fe₂O₃/O−CNT exhibits a low onset potential of 260 mV and overpotential 310 mV @ 10 mA cm⁻² for oxygen evolution. Being a Mott-Schottky catalyst, it achieves the higher flat band potential of −1.15 V with the carrier density of 0.173×10²⁴ cm⁻³. Further, in presence of 1 M CH₃OH, it delivers the MOR current density of 10 mA cm⁻² at 1.46 V vs. RHE. The excellent electrocatalytic OER and MOR activity of Ni−Fe₂O₃/O−CNT could be attributed to the synergistic interaction between Ni-doped Fe₂O₃ and O−CNT.