Intercalating assembly of NiFe LDH nanosheets/CNTs composite as high-performance electrocatalyst for oxygen evolution reaction

Abstract

Layered double hydroxides (LDH) possess high intrinsic catalytic activity for oxygen evolution reaction (OER); however, the low electronic conductivity hinders their further development as high-performance electrocatalysts. To address this problem, NiFe LDH is synthesized and exfoliated into positively charged nanosheets, followed by assembling with negatively charged carbon nanotubes (CNTs). Under the effect of electrostatic interaction, NiFe LDH and CNTs layers are alternately stacked to form an intercalating heterostructure of NiFe LDH/CNTs. This unique configuration provides both sufficient active sites and efficient charge/electron transport channels for OER electrocatalysis. By tuning the relative amounts of NiFe LDH and CNTs, the optimized composite only needs a low overpotential of 234 mV (vs. RHE) to reach a current density of 10 mA cm−2, showing better OER activity than that of RuO2. The excellent performance should be attributed to the synergy between active NiFe LDH and conductive CNTs, as well as the intercalated structure with high accessible surface area.