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

Abstract

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.