Ultrafine Pd@MnO/NC heterojunction nanocatalyst for efficient oxygen reduction reaction
摘要
The development of efficient and stable electrocatalysts is key to improving the performance of rechargeable zinc–air batteries (ZABs). In recent years, metal–metal oxide heterostructures have demonstrated broad application prospects in electrocatalysis owing to their unique electronic synergistic effects. Nevertheless, challenges remain in simplifying their preparation processes and further enhancing their catalytic performance. In this work, we synthesized a superfine Pd@MnO/NC heterojunction superfine nanocatalyst via a one-pot strategy based on the self-assembly of cyclodextrin and metal ions. The as-prepared Pd@MnO/NC heterojunction nanoparticles (~ 2.25 nm) were uniformly dispersed on nitrogen-doped mesoporous carbon with a high specific surface area (746.12 m2 g⁻1). The Pd@MnO/NC catalyst exhibited exceptional oxygen reduction reaction (ORR) performance, achieving: A half-wave potential of 0.894 V (vs. RHE). A limiting current density of 5.2 mA cm⁻2. Notably, the catalyst maintained 88.9% of its initial current density after 12 h of continuous operation, demonstrating superior stability compared to commercial Pt/C (81.8%). Furthermore, it displayed excellent methanol tolerance, highlighting its potential for practical applications. The assembled zinc–air battery demonstrated a remarkable peak power density of 156.45 mW cm⁻2 and a specific capacity of 782.85 mAh g⁻1, significantly outperforming commercial Pt/C catalysts. The strong electronic interaction between Pd and MnO not only facilitated charge transfer but also optimized the adsorption–desorption behavior of oxygen intermediates, thereby substantially enhancing the catalytic performance. This study not only provides a high-performance catalyst for ZABs but also offers novel design principles and synthetic strategies for developing metal–oxide heterojunction electrocatalysts.