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 mAcm (-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. (c) 2020 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.