Pt Nanoparticles Anchored on Cu-MOF-74: An Efficient and Durable Ultra-low Pt Electrocatalyst toward Oxygen Reduction Reaction

Abstract

Catalysts for slow oxygen reduction reaction (ORR) are of great importance for long-term operation and wide application for the cathode of proton exchange membrane fuel cells (PEMFCs). Herein, an efficient approach used for the rational synthesis of an effective ORR electrocatalyst by encapsulating Pt nanoparticles with ultra-low content (0.5, 1.0, 1.5 wt.% Pt) on the surface of a copper-based organic metal frame (Cu-MOF-74) and then carbonized at 900 °C, for the first time. The catalyst Pt1%/Cu/NC-900 from the series of prepared catalysts exhibits a highly efficient ORR activity with an onset potential (Eo) 1.01 V vs RHE and half-wave potential (E1/2) 0.88 V vs RHE compare to commercial Pt/C (Eo 0.96 V and E1/2 0.86 V vs RHE). It has also displayed excellent long-term stability in an alkaline solution. The Pt1%/Cu/NC-900 performance and stability are dramatically improved, which may be attributed to the interaction of Pt with Cu and carbon carriers. Such an architecture provides an efficient approach for direct application of MOFs to electrocatalysts. To the best of our knowledge, this is the first time we have used bimetallic Pt-Cu catalysts with ultra-low Pt contents for the ORR in the alkaline solution with superior activity than commercial Pt/C.