Self-assembly of NiFe-LDH with birnessite via electrostatic attraction towards high-performance OER catalyst

Abstract Two-dimensional birnessite (NaMnO) with a large lateral size and low thickness was synthesized by a molten-salt method and assembled with nanosheets of NiFe layered double hydroxides (LDH) via electrostatic attraction. The hybrid structure shows excellent efficiency in electrocatalytic oxygen evolution reaction with a small overpotential of about 260 mV at a current density of 20 mA cm−2 and Tafel slope of 21 mV dec−1, superior to the prisitine components, their physical mixture and commercial RuO2. The enhancement is attributed to the intimate contact between the two components, which guarantees efficient charge transfer across the interface and exposes more active sites by preventing the LDH from aggregation.