Establishing proper intrinsic catalysts with nanostructured high active surfaces endows the paramount electrocatalytic activity. A Ni-Se@Cu-Ni/NF catalyst for hydrogen and oxygen evolution reactions (HER and OER) is prepared via an efficient two-step pulse current (PC) electrodeposition method. The initial 3D film of Cu-Ni is synthesized via the dynamic hydrogen bubble template (DHBT) method to attain further active surface area. Then, Ni-Se film is prepared by direct current (DC) and PC electrodeposition. Morphological, chemical, and electrocatalytic characteristics of the Ni-Se electrodeposited films are evaluated. X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy results show a NiSe/NiSe2 nanofilm on the 3D microporous nanostructured Cu-Ni substrate which reveals an efficient bifunctional electrocatalytic behavior with overpotentials of 74 and 272 mV in the current density of 10 mA cmâ2, and Tafel slopes of 78 and 50 mV decâ1 for HER and OER, respectively. The two-electrode examination with NiSe/NiSe2@Cu-Ni/NF catalyst in overall water splitting indicates a required potential of 1.57 V in the current density of 10 mA cmâ2.