Interface construction of Ni(OH)2/Fe3O4 heterostructure decorating in-situ defected graphite felt for enhanced overall water splitting

There is a persistent need to design efficient and cheap electrode materials for water electrolysis. Herein, a hierarchical Ni(OH)2/Fe3O4/graphite felt (GF) (NFGF) heterostructure bifunctional electrocatalyst is tailordesigned to accelerate the water splitting process via boosting the heterostructure interfaces. A facile electrochemical method is probed to synthesize NFGF heterostructure with in-situ GF surface functionalization. Various analyses are used to demonstrate the GF in-situ surface functionalization and interface engineering. Remarkably, NFGF displays boosted hydrogen and oxygen evolution reactions by presenting a low overpotential of -50 mV and 281 mV at a current density of 10 mA cm-2 and 30 mA cm- 2, respectively. Thus, NFGF is tested as a bifunctional electrocatalyst in the two-electrode cell and demonstrates a low cell voltage of 1.55 V at a current density of 10 mA cm- 2 with outstanding performance over a long time of electrolysis up to 24 h.