ZIF-derived ternary Pt-Co-Ni alloy as the superior active and durable catalyst for PEMFC

The commercialization of proton exchange membrane fuel cells (PEMFCs) is impeded by the lack of active and durable cathode catalysts in acidic environments. Binary or ternary platinum-based alloys have been recognized as one of promising candidates to decrease the utilization of platinum amounts, while the activity and stability of the ternary catalysts require further improvements. Herein, we report a novel approach to prepare PtCoNi@NG composite structured catalysts anchored by graphene N/O functional groups via in-situ growing multi-metal-organic-framework (multi-MOF). The introduction of Ni motivates strong interaction among the Pt-Co-Ni alloy and the N/O functional groups on the graphene carrier, conferring high catalyst activity and excellent stability towards oxygen reduction reaction (ORR) in acidic media. The optimal PtCo30Ni10 @NG catalyst shows superior performance in an acidic medium, exhibiting a half-wave potential up to 0.9322 V and high mass activity of 1.3567 A mgPt−1 (9.87 times higher than commercial Pt/C catalyst). A high peak power density of 0.866 W cm−2 at H2/Air (150 kPaabs) and 2.031 W cm−2 at H2/O2 (250 kPaabs) condition is achieved in a PEMFC with PtCo30Ni10 @NG as the cathode catalyst (0.1 mgPt cm−2). Hence, this work provides critical sights into constructing efficient catalysts by ternary platinum-based alloys strategy and anchoring effect by graphene N/O groups.