Enhanced Bifunctional Catalysis of Iridium Nanoparticles on Nitrogen-Doped Holey Carbon via Strong Metal-Support Interaction for Rechargeable Zinc-Air Batteries.

Developing efficient and durable catalysts is crucial for the practical application of energy storage and conversion technologies. This work reports the synthesis of iridium nanoparticles supported on nitrogen-doped holey carbon (Ir-NHC), which exhibit outstanding performance in both oxygen evolution reaction (OER) and oxygen reduction reaction (ORR), leading to impressive device performance in rechargeable zinc-air batteries (ZABs). Compared to commercial Pt/C + Ir/C, Ir-NHC demonstrates a 1.6-fold higher specific capacity (862.5 mAh g-1 versus 536.9 mAh g-1), a similar power density of 120.0 mW cm-2, and remarkable cycling stability (2000 cycles versus ∼32 cycles). A series of X-ray-based spectroscopic characterizations reveal a strong metal-support interaction between the Ir nanoparticles and the NHC support. This interaction enables precise control over the size and electronic structure of the Ir nanoparticles. In situ X-ray absorption fine structure studies conducted at various OER potentials demonstrate that the electronic structure of Ir and the adsorption process of OER intermediates are optimized by this interaction, leading to the observed excellent catalytic activity and stability of Ir-NHC.