Heterogeneous ultra-thin FeCo-LDH@Co(OH)2 nanosheets facilitated electrons transfer for oxygen evolution reaction

Developing cost efficient, robust, non-precious metal electrocatalysts for oxygen evolution reaction (OER) is a significant challenge in water splitting for renewable energy conversion. A novel electrocatalyst of heterogeneous ultra-thin FeCo-LDH@Co(OH)2 nanosheets derived from 2D Zeolitic imidazolate framework facilitated electrons transfer for OER. DFT calculation revealed that heterogeneous interfaces reduced adsorption energy barriers of intermediates in rate-determining step of OER. The CoOOH with higher CoIII valence state derived from surface reconstruction, which was detected via in-situ Raman spectroscopy, activated O ions to provide higher intrinsic activity. XPS results confirmed that electrons transfer from Co(OH)2 to FeCo-LDH accelerated alkaline OER kinetics. The FeCo-LDH@Co(OH)2–0.5 exhibited low overpotentials of 230 mV at 10 mA cm−2 and maintained long durability for 300 h. This study opened up a new method for design and synthesis of ultrathin LDHs electrocatalysts.