Hollow porous MnFe2O4 sphere grown on elm-money-derived biochar towards energy-saving full water electrolysis.

The development of inexpensive and efficient bifunctional electrocatalysts is significant for widespread practical applications of overall water splitting technology. Herein, a one-pot solvothermal method is used to prepare hollow porous MnFe 2 O 4 sphere, and which growing on natural abundant elm money derived biochar material to construct MnFe 2 O 4 /BC composite. When the overpotential is 156 mV for both oxygen evolution reaction and hydrogen evolution reaction, the current density reaches up to 10 mA cm -2 , and its duration is 10h. At 1.51 V, the overall water decomposition current density of 10 mA cm -2 can be obtained in 1M KOH. This work proves that elm money derived biochar is a valid substrate for hollow porous sphere growing. MnFe 2 O 4 /BC give a promising general strategy for preparing the effective and stable bifunctional catalysis that can be expand to multiple transition metal oxide.