FeNi-LDH nanoflakes on Co-encapsulated CNT networks for stable and efficient ampere-level current density oxygen evolution

Abstract

Developing low-cost but efficient electrocatalysts for continuous oxygen evolution reaction (OER) at ampere-level current densities can promote the hydrogen economy. LDHs are promising electrocatalysts to replace noble-metal-based catalysts for efficient OER, and rationally constructing LDH-based heterostructures can further boost their OER activities. Herein, we report the anchoring of FeNi-LDH nanoflakes onto MOF-derived carbon nanotube (CNT) networks on carbon cloth to obtain the self-supported LDH/CNT/CC. Benefiting from the advantages of its CNT network and the highly-active sites of its three-layer heterostructure, the optimized LDH/CNT/CC only requires a low overpotential of 200 mV at 10 mA cm and exhibits robust stability under continuous electrolysis for 160 h at an ampere-level current density of 1 A cm. Theoretical calculations show three-layer FeNi-LDH(001)/graphene(002)/Co(111) slab has the lowest OER energy barrier, and its graphene layer can gain electrons from the FeNi-LDH and Co to show the most suitable binding strength for intermediates to facilitate OER.