Proton exchange membrane fuel cells (PEMFC) has been widely recognized as a promising renewable energy devices. However, platinum (Pt) is often required to promote the sluggish oxygen reduction reaction (ORR) occurring at cathode, which severely hinders the commercialization of PEMFC. Therefore, it is urgent to develop active and cost-effective electrocatalysts. Recently, Pt-based Intermetallic nanocrystals (iNCs) are now attracting much attention due to their well-define electronic structure, composition. However, high temperature annealing is usually required to obtain iNCs, which will cause particle sintering. Though MgO or SiO2 shell is usually used as robust layer to prevent aggregation, the synthetic procedure will be complicated as a result and it is not favorable for scale-up synthesis. Here, a facile and robust self-protection method is developed towards 3 nm PtM (M = Zn, Ga or Cu) iNCs. To be specific, L10-PtZn NPs are synthesized by thermal annealing of Pt@ZnO matrix followed by acid washes. These ordered L10-PtZn exhibit higher catalytic performance for ORR than commercial Pt/C and disordered counterparts. More importantly, these L10-PtZn iNCs demonstrate much enhanced stability even after 50k potential cycles in acid at 60 degree C thanks to the unique ordered structure.

Self-protection method to ultrasmall intermetallic PtM (M = Zn, Ga or Cu) nanocrystals as efficient electrocatalysts for oxygen reduction reaction

2019 Spring National Meeting

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