Construction of Petal‐Like CoO/CoP Heterostructures by Oxygen Vacancy Induced P‐doping for Efficient Overall Water Splitting

Hydrogen energy has become a green, high‐efficiency new energy source due to its superior characteristics. Overall water splitting is considered as an effective method for hydrogen production. However, the synthesis of non‐noble metal‐based robust bi‐functional electrocatalysts for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are still challenging. Here, the synthesis of petal‐like CoO/CoP heterostructures is reported by an oxygen vacancy induced P‐doping strategy. The oxygen defect sites of the defective Co 3 O 4–x easily attract phosphorus atoms to enhance the P‐doping process, which induces the formation of a two‐dimensional CoO/CoP heterojunction structure. Due to the synergistic effect between CoP and CoO phases in the catalyst, the heterostructures can well drive the hydrogen and oxygen evolution reactions under alkaline conditions, and thus substantially promotes overall water splitting with a relatively low potential 1.64 V at 10 mA cm −2 without decay even after the durability test for 24 h.