The In‐situ Growth of Ru Modified CoP Nanoflakes on Carbon Clothes as Efficient Electrocatalysts for HER**

Abstract Exploring highly efficient, durable and low‐cost catalysts for hydrogen evolution reaction (HER) is crucial to promoting the development of electrochemical water splitting systems but remains challenging. In this work, the Ru‐modified CoP nanoflakes on carbon clothes (Ru‐CoP/CC) are fabricated via an in‐situ hydrothermal method, followed by low‐temperature phosphatized treatments. According to X‐ray photoelectron spectroscopy (XPS) measurements, the Ru doping induces the electron deviation from Ru to Co−P, and makes Co ions be an electron‐rich state. It is revealed that the introduction of Ru can effectually reconstruct the electron coordination environment of Co−P. The resultant Ru‐CoP/CC catalyst shows outstanding HER performance with an ultralow overpotential of 45 mV at 10 mA cm −2 . Moreover, the obtained catalyst exhibits long‐term durability at 20 mA cm −2 for 20 h in the alkaline solution. This work opens a new avenue to lower the usage of noble metal in electrocatalyst and helps to developing a high‐performance electrocatalyst for HER.