Micropore-confined ultrafine Pt nanoparticles in hierarchical porous carbon nanofibers for pH-universal oxygen reduction with enhanced stability

Abstract

Carbon-supported platinum (Pt/C) is the most extensively used electrocatalyst for the oxygen reduction reaction (ORR). However, the electrochemical degradation occurring during operation severely restricts the catalyst's cycling stability, posing a critical obstacle for practical commercialization. Here, we developed a high-performance alternative electrocatalyst consisting of ultrafine Pt nanoparticles embedded in hierarchical porous carbon nanofibers (Pt/PCNF). Importantly, we elucidate a novel micropore confinement effect, demonstrating through DFT calculations that micropores serve as high-surface-area anchoring sites for Pt species, effectively stabilizing them. This unique architecture facilitates ultrahigh Pt dispersion, endowing the catalytic with exceptional stability for pH-universal ORR. Remarkably, the Pt/PCNF catalyst achieves 70 % higher electrochemically active surface area than commercial Pt/C while maintaining 99.4 % of its initial activity after 10,000 durability cycles. Furthermore, when integrated into Zn-air batteries, the catalyst delivers a high open-circuit voltage (1.42 V) and remarkable peak power density (216.73 mW cm⁻²). This work provides fundamental insights into the stabilization mechanisms of Pt-based ORR catalysts through micropore confinement, while demonstrating exceptional performance metrics that meet industrial requirements for fuel cell applications.