Hollow Porous MnFe2O4 Sphere Grown on Elm‐Money‐Derived Biochar towards Energy‐Saving Full Water Electrolysis

• Published in: Chemistry : a European journal 2020-11, Vol.26 (63), p.14397-14404
• Main Authors: Liu, Xia, Huo, Yu‐Qiu, Yan, Li‐Kai, Fan, Na, Cai, Kui‐Zhe, Su, Zhong‐Min
• Format: Article
• Language: English
• Subjects: biochar; Catalysis; Charcoal; Chemistry; Construction materials; Current density; Electrocatalysts; Electrolysis; Elm; Energy conservation; hollow porous sphere; hydrogen evolution reaction; Hydrogen evolution reactions; MnFe2O4; oxygen evolution reaction; Oxygen evolution reactions; Substrates; Transition metal oxides; Water conservation; Water splitting
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.202002134

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 MnFe2O4 spheres, which are grown on natural‐abundant elm‐money‐derived biochar material to construct MnFe2O4/BC composite. When the overpotential is 156 mV for both the oxygen evolution reaction and the hydrogen evolution reaction, the current density reaches up to 10 mA cm−2, and its duration is 10 h. At 1.51 V, the overall water decomposition current density of 10 mA cm−2 can be obtained in 1 m KOH. This work proves that elm‐money‐derived biochar is a valid substrate for growing hollow porous spheres. MnFe2O4/BC give a promising general strategy for preparing the effective and stable bifunctional catalysis that can be expand to multiple transition metal oxide. A one pot solvothermal method is used to prepare MnFe2O4 hollow porous spheres and an elm‐money‐derived biochar composite (MnFe2O4/BC) catalyst. The catalyst exhibits excellent performance in alkaline medium with the low overpotential of 156 mV for both the oxygen and hydrogen evolution reaction at the current density of 10 mA cm−2. An alkaline electrolytic cell capitalizing on MnFe2O4/BC as bifunctional electrocatalysts achieved an overall water splitting current density of 10 mA cm−2 at a cell voltage of 1.51 V.