The key issue in alkaline water electrolysis for hydrogen production is that a significant efficiency loss happens at the anode during the oxygen evolution reaction (OER).Thus,it is critical to develop an inexpensive and robust catalyst with high electrochemical activities.After billions of years of evolution,manganese has played a central role in the PSⅡ system for the OER.Manganese oxides (MnO2) are widely abundant in earth (～0.1 ％ in the curst).