A universal and controllable strategy of constructing transition-metal nitride heterostructure for highly enhanced bifunctional electrocatalysis
Transition-metal nitride heterostructure has attracted increasing attention due to its unique structure and amazing synergetic properties, which is expected to synchronously achieve bifunctional applications. However, the classical bifunctional electrocatalysts usually show outstanding activity for one half reaction at the expense of the ability of another half-reaction, thus give a moderate performance for overall water splitting. In this work, a family of transition metal nitride heterostructures (MxN@NiMoN, M: Ni, Co and Cu) were synthesized by a general and effective strategy to address the shortcomings of classical bifunctional electrocatalysts. These materials exhibited excellent performances for both hydrogen and oxygen evolution reaction (HER/OER) which were superior or comparable to that of noble metal. Boosted electrocatalytic overall water splitting was also achieved with only a low cell voltage of 1.481 V to drive 10 mA.cm-2. Moreover, the excellent durability of 2 days illustrated superior value in practical applications. This work provides fundamental insight towards designing and optimizing advanced materials for renewable energy applications.