Hierarchical tremella flower of P-doped cobalt molybdenum oxide/layered double hydroxide nanocomposite as bifunctional electrocatalysts for overall water splitting

Electrolysis of water is an environmental protection technology to generate hydrogen and alleviate energy depletion problem. In this paper, the hierarchical tremella flower composite was fabricated by nickel‑iron layered double hydroxide (NiFeLDH) and nonmetallic phosphorus-doped cobalt molybdenum oxide (P-CMO). A good deal of uniform nanosheets with the thickness of ∼48 nm constitute three-dimensional (3D) flower architecture. Compared with NiFeLDH and P-CMO, the P-CMO/NiFeLDH exhibits excellently electrocatalytic activity in oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), achieving the overpotentials (ƞ 10 ) of 254.9 mV and 96.3 mV as well as the Tafel slopes of 35.5 mV dec −1 and 79.2 mV dec −1 , respectively. Furthermore, it requires a cell voltage of 1.43 V to reach a current density of 10 mA cm −2 in an electrolyzer consisting of P-CMO/NiFeLDH as both anode and cathode. The characterizations and density functional theory (DFT) calculations demonstrate that the interfacial synergism of P-CMO/NiFeLDH can induce the electron redistribution by charge transfer from NiFeLDH to P-CMO, augment the generation of high valence nickel, decrease the reaction energy barrier and enhance the reaction kinetics. This work declares that the layered double hydroxide integrated with heteroatom-substitutional transition metal oxide furnishes an affordable route for devising efficient electrocatalysts in water-splitting application.