Co doped NiFe LDH nanosheets in situ anchored on MXene for the highly efficient oxygen evolution reaction in water splitting

Abstract

The development of efficient, low-cost, and long-lasting electrocatalysts is critical for enhancing the oxygen evolution reaction (OER) in alkaline water splitting. Herein, we successfully synthesized a novel MXene (Ti₃C₂T_x) supported Co-doped NiFe layered double hydroxide (NiFeCo_0.75 LDH@Ti₃C₂T_x) by the simple solvothermal method. The morphology of NiFeCo_0.75 LDH@Ti₃C₂T_x was characterized using scanning electron microscopy. The electrocatalytic performance of NiFeCo_0.75 LDH@Ti₃C₂T_x was measured by linear sweep voltammetry. The NiFeCo_0.75 LDH@Ti₃C₂T_x catalyst exhibited superior OER activity with the uniform dispersion of NiFeCo_0.75 LDH nanosheets uniformly dispersed on the Ti₃C₂T_x support. The overpotential of NiFeCo_0.75 LDH@Ti₃C₂T_x at current densities of 10 and 300 mA cm⁻² is only 258 and 330 mV, respectively, which is significantly lower than those of NiFeCo_0.75 LDH (259 mV and 351 mV) and NiFe LDH (270 mV and 374 mV), respectively. Additionally, the NiFeCo_0.75 LDH@Ti₃C₂T_x catalyst achieved a Tafel slope of 44.78 mV dec⁻¹ and demonstrated excellent long-term stability for over 400 h at 10 mA cm⁻². Furthermore, the OER catalytic mechanism of Co doped NiFe LDH@Ti₃C₂T_x was preliminarily discussed. The results show that the MXene support and Co doping effectively tailors the electronic structure and D-band center of LDH, thereby boosting the OER performance of NiFeCo_0.75 LDH@Ti₃C₂T_x.