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-DH/CFC) for OER application. It is found that the optimal NiCoFe-LDH/CFC with 1 h CER exhibited superior OER activity than pristine NiCo-LDH material and commercial Ir/C electrode including a low onset overpotential (eta) of only 240 mV and a low overpotential of 280 mV to achieve a current density of 10 mA cm(-2) in 1 M KOH electrolyte. The Tafel slope decreased from 63 mV dec(-1) for pristine NiCo-LDH material to 34 mV dec(-1) for NiCoFe-LDH/CFC with 1 h CER. At an overpotential of 0.3 V, an over 16.5 times of improvement of the turnover frequency (TOF) of NiCoFe-LDH/CFC with 1 h CER (0.0347 s(-1)) was achieved compared to NiCo-LDH (0.0021 s(-1)). The NiCoFe-LDH/CFC with 1 h CER demonstrated a retention rate of 98% after 10 h stability testing. All the results demonstrate the excellent electrocatalytic activity of NiCoFe-LDH/CFC for OER applications. (C) 2017 Elsevier Ltd. All rights reserved.