ZIF derived PtCo alloys-based nitrogen-doped Graphene as cathode catalyst for proton exchange membrane fuel cell

Abstract

The proton exchange membrane fuel cell (PEMFC) has gained a lot of attention due to its ability to provide electrical energy with high efficiency and minimal environmental pollution. However, platinum-based nanomaterials, as the most commonly used electrocatalysts, have very limited global reserves and high prices, posing significant barriers to widespread commercialization of PEMFC. Here, we present a novel method for preparing a Co-ZIF supported PtCo alloy catalyst for the oxygen reduction reaction (ORR). The precursor Co-ZIF doped graphene oxide (Co-ZIF@GO) is obtained by in-situ controlled growth of ZIF-67 nanocrystals on two surfaces of graphene oxide (GO) sheets with different nanoscale dimensions. PtCo alloys-based nitrogen-doped graphene (PtCoNG) cathode catalyst with well-dispersed PtCo alloy nanoparticles (∼5 nm) is obtained after pyrolysis and platinum loading. The optimal PtCoNG catalyst outperforms the commercial Pt/C catalyst in terms of performance and stability in acidic media, with a half-wave potential of up to 0.86 V vs reversible hydrogen electrode (RHE) and three times the mass activity. It demonstrates that this new synthesis method provides an effective strategy for developing active and stable Pt alloy catalysts by in-situ growing ZIF on graphene oxide.