Synergistic cerium doping and MXene coupling in layered double hydroxides as efficient electrocatalysts for oxygen evolution

Oxygen evolution reaction (OER) is a bottle-neck process in many sustainable energy conversion systems due to its sluggish kinetics. The development of cost-effective yet efficient electrocatalysts towards OER is highly desirable but still a great challenge at current stage. Herein, a new type of hybrid nanostructure, consisting of two-dimensional (2D) Cerium-doped NiFe-layered double hydroxide nanoflakes directly grown on the 2D Ti3C2Tx MXene surface (denoted as NiFeCe-LDH/MXene), is designed using a facile in-situ coprecipitation method. The resultant NiFeCe-LDH/MXene hybrid presents a hierarchical nanoporous structure, high electrical conductivity and strong interfacial junction because of the synergistic effect of Ce doping and MXene coupling. As a result, the hybrid catalyst exhibits an excellent catalytic activity for OER, delivering a low onset overpotential of 197 mV and an overpotential of 260 mV at a current density of 10 mA·cm−2 in the alkaline medium, much lower than its pure LDH counterparts and IrO2 catalyst. Besides, the hybrid catalyst also displays a fast reaction kinetics and a remarkable stable durability. Further theoretic studies using density function theory (DFT) methods reveal that Ce doping could effectively narrow the bandgap of NiFe-LDH and reduce the overpotential in OER process. This work may shed light on the exploration of advanced electrocatalysts for renewable energy conversion and storage systems.