MXene-supported NiMn-LDHs as efficient electrocatalysts towards enhanced oxygen evolution reactions

Abstract

Layered double hydroxides (LDHs) are recognized as potential electrocatalysts for oxygen evolution reactions (OERs), whereas their poor electrical conductivity restricts their practical application. Herein, two-dimensional (2D) NiMn-LDHs on the surface of 2D Ti₃C₂ MXene are synthesized via a facile hydrothermal method. It is found that a thin layer of NiMn-LDHs is firstly deposited on the surface of Ti₃C₂ MXene, and gradually it extends out of the surface for continuous growth, and finally the 2D/2D hybrid structure is constructed. Owing to this unique feature of such a kind of 2D/2D hybrid, the NiMn-LDHs/Ti₃C₂-MXene hybrids (NT-10) show an overpotential of 294 mV at a current density of 10 mA cm⁻² and a Tafel slope of 83.7 mV dec⁻¹ in 1 M KOH solution. The results demonstrate the outstanding electrocatalytic OER performance which surpasses those of pristine NiMn-LDHs and commercial IrO₂ catalysts. Theoretical studies reveal that the coupling effect between Ti₃C₂ MXene and NiMn-LDHs could effectively narrow the bandgap of NiMn-LDHs and modulate their electronic structures, which could greatly boost the oxygen-evolving performances and reaction kinetics. In principle, this work provides a facile and effective strategy to boost the electrocatalytic OER performance of NiMn-LDHs.