The design of cost-effective and earth-abundant bifunctional electrocatalysts for highly efficient oxy-gen evolution reaction(OER)and hydrogen evolution reaction(HER)is important for water splitting as an advanced renewable energy transformation system.In this work,the self-supporting amorphous NiFeCoP catalyst with nanoporous structure via a facile electrochemical dealloying method is reported.Benefiting from the bicontinuous nanostructure,disordered atomic arrangement,abundant active sites and synergic effect of various transition metals,the as-prepared nanoporous NiFeCoP(np-NiFeCoP)cat-alyst exhibits good electrocatalytic activity,which achieves the current densities of 10 mA cm-2 at low overpotentials of 244 mV and 105 mV for OER and HER in 1.0 M KOH,respectively.In addition,the bifunc-tional electrocatalyst also shows outstanding and durable electrocatalytic activity in water splitting with a small voltage of 1.62 V to drive a current density of 10 mA cm-2 in a two-electrode electrolyzer system.The present work would provide a feasible strategy to explore the efficient and low-cost bifunctional electrocatalysts toward overall water splitting.