Ternary NiCoFe Layered Double Hydroxide Nanosheets Synthesized by Cation Exchange Reaction for Oxygen Evolution Reaction

Abstract

Developing suitable catalysts which can accelerate the sluggish oxygen evolution reaction (OER) process is of high importance to fulfil the mission of hydrogen generation by water splitting. Herein, we demonstrate a facile method based on cation exchange reaction (CER) for preparation of NiCoFe layered double hydroxide (LDH) nanosheet arrays which directly grafted on flexible carbon fiber clothes (NiCoFe-LDH/CFC) for OER application. It is found that the optimal NiCoFe-LDH/CFC with 1h CER exhibited superior OER activity than pristine NiCo-LDH material and commercial Ir/C electrode including a low onset overpotential (η) of only 240mV and a low overpotential of 280mV to achieve a current density of 10mAcm−2 in 1M KOH electrolyte. The Tafel slope decreased from 63mVdec−1 for pristine NiCo-LDH material to 34mVdec−1 for NiCoFe-LDH/CFC with 1h CER. At an overpotential of 0.3V, an over 16.5 times of improvement of the turnover frequency (TOF) of NiCoFe-LDH/CFC with 1h CER (0.0347s−1) was achieved compared to NiCo-LDH (0.0021s−1). The NiCoFe-LDH/CFC with 1h CER demonstrated a retention rate of 98% after 10h stability testing. All the results demonstrate the excellent electrocatalytic activity of NiCoFe-LDH/CFC for OER applications.