CoFeNi based trifunctional electrocatalysts featuring in-situ formed heterostructure

All-in-one transition metal-based electrocatalysts with high activities towards different reactions in aqueous electrolytes are of critical importance as they can dramatically bring down the cost of relevant energy devices. Herein a facile and low-cost synthesis of CoFeNi nanoparticles encapsulated by an N-doped carbon layer has been developed by pyrolyzing Prussian blue (PB) precursors. The obtained catalyst features tri-catalytic activity towards OER, ORR, and HER reactions in alkaline and acidic condition, and show great potential as a catalyst for water splitting and anode material for Zinc-Air batteries. Moreover, compared with the single phase, the sample with the heterostructure composed of both fcc and bcc phases exhibited dramatic enhancement in multi-catalytic activity. The heterostructure originates from an in-situ phase separation induced by composition variation. This demonstrates the effectiveness of heterostructure engineering introduced by in-situ phase separation in boosting the multi-catalytic activity.