Promotion effect of intercalated citrate anion on the reconstruction of NiFe LDH for oxygen evolution reaction†

Abstract

The reconstruction of pre-catalysts is a powerful strategy to achieve efficient oxygen evolution reaction (OER) electrocatalysts under alkaline conditions. Herein, NiFe based layered double hydroxides (LDHs) intercalated with citrate anions (CA) are constructed as pre-catalysts via a one-pot hydrothermal method. The CA intercalation exhibits an obvious promotion effect on structure reconstruction, which improves the OER performance. Benefiting from promoted structure reconstruction, a low overpotential of 241 mV at 50 mA cm⁻², and an ultralow Tafel slope of 36.4 mV dec⁻¹ can be achieved with robust durability (over 82 h at 50 mA cm⁻²), demonstrating better OER performance than that of NiFe LDH without CA intercalation. The addition of CA into the electrolyte could enhance the OER activity, indicating surface-adsorbed CA promotes the OER activity of NiFe LDHs. Our findings provide new insight into the effect of anions on catalyst reconstruction and provide a new way of developing efficient electrocatalysts.