Trace cobalt-inserted platinum lattice gap to enable bifunctional oxygen electrocatalysis

Platinum-based materials are generally considered efficient oxygen reduction reaction (ORR) electrocatalysts but show poor performance for oxygen evolution reaction (OER), which limits their applications in zinc-air batteries (ZABs). Therefore, it is of great importance to develop highly effective bifunctional ORR and OER Pt-based electrocatalysts. Herein, a Co atom-inserted Pt lattice gap electrocatalyst (Co-Pt@Fe-N-C) was constructed. Experimental and theoretical calculations illustrated that the insertion of Co caused the lattice expansion of Pt nanocrystal and increased the Pt electron density, thereby upshifting the Pt d-band center. Benefiting from this, the interactions between Pt active sites and ORR/OER intermediates were stabilized, which improved the ORR/OER electrocatalytic performances. A half-potential of 0.89 V vs. RHE for ORR and narrow ORR/OER potential gap (0.75 V) were achieved, and Co-Pt@Fe-N-C-based ZABs exhibited a stable open circuit potential of 1.52 V, peak power density of 151 mW cm⁻², and over 850 hours of stability. Thus, our work has significant potential to guide future research works on the design of effective Pt-based ORR/OER bifunctional electrocatalysts and ZABs.