Compressing Platinum Lattices for Durable Oxygen Electrocatalysis in Zinc-Air Battery Cathodes

The trade-off between activity and stability has long hindered the development of high-performance platinum (Pt) catalysts for the oxygen reduction reaction (ORR). Here, we present a synergistic strategy to simultaneously overcome this limitation by engineering compressive lattice strain in Pt nanocrystals via a controlled graphene oxide (GO) overlay. Our approach involves the thermal reduction of GO wrapped around hollow carbon sphere-supported Pt nanoparticles (HCS-Pt). During this process, the contraction of the thermally reduced GO (rGO) shell precisely induces a compressive strain in the underlying Pt(111) lattice. Remarkably, we find that the strain can be finely tuned by the reduction temperature, following a distinctive volcano-type relationship. The optimized HCS-Pt@rGO catalyst achieves a 3.6% compressive strain, which shifts the d-band center of Pt upward and optimizes the adsorption energy of oxygen intermediates. This electronic effect lowers the kinetic barrier of the ORR rate-determining step, resulting in a 25 mV positive shift in the half-wave potential. When implemented as a cathode in a zinc-air battery, this catalyst delivers markedly enhanced cycling stability. This work demonstrates that rational strain engineering via a protective shell can resolve the activity-stability paradox, offering a new pathway for the design of cost-effective electrocatalysts.