Heterogeneous NiFeCoP/NF Nanorods as a Bifunctional Electrocatalyst for Efficient Water Electrolysis

The exploitation of transition metal phosphates (TMPs)‐based catalysts with excellent activity and stability toward both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) for water electrolysis is imperative but challenging. Herein, we report a novel heterostructured Ni2P−Fe2P−Co2P−Ni5P4 nanorods derived from a NiFe LDH@ZIF‐67 precatalyst on 3D self‐supported Ni foam (NiFeCoP/NF) for water electrolysis. Owing to systematically engineering the composition, structure, and morphology of catalyst, which not only increase the intrinsic activity and create more accessible catalytic activity centers, but also accelerate electron transfer and promote the gas release, the designed NiFeCoP/NF achieves synergistically enhanced catalytic performance towards OER and HER. The as‐prepared NiFeCoP/NF electrode exhibits excellent activities with low overpotentials of 244.2 mV for OER and 167.5 mV for HER, respectively to reach a current density of 100 mA cm−2 in 1.0 KOH solution, as well as outstanding stability for 140 h at 500 mA cm−2. Additionally, a water electrolysis device constructed with the NiFeCoP/NF electrode as both the anode and cathode only needs a low cell voltage of 1.564 V to achieve 30 mA cm−2. This work presents a viable way for developing the high catalytic performance of TMPs‐based bifunctional electrocatalysts via designing and regulating the electronic structure and morphology. Electrocatalysis: Heterogeneous trimetallic phosphide (Ni2P−Fe2P−Co2P−Ni5P4) nanorods derived from an NiFe LDH@ZIF‐67 precatalyst on Ni foam (NiFeCoP/NF) as self‐supported electrodes for water electrolysis are reported. The enhanced OER/HER performances for NiFeCoP/NF electrode was achieved by improving the quantity and quality of active sites, facilitating the release of O2/H2 bubbles, enhancing conductivity and electron transfer. Moreover, the water‐alkali electrolyzer assembled by NiFeCoP/NF as both anode and cathode only needed 1.564 V to deliver 30 mA cm−2 with an excellent stability.