An Oxygen‐Vacancy‐Rich Semiconductor‐Supported Bifunctional Catalyst for Efficient and Stable Zinc–Air Batteries

The highly oxidative operating conditions of rechargeable zinc–air batteries causes significant carbon‐support corrosion of bifunctional oxygen electrocatalysts. Here, a new strategy for the catalyst support design focusing on oxygen vacancy (OV)‐rich, low‐bandgap semiconductor is proposed. The OVs promote the electrical conductivity of the oxide support, and at the same time offer a strong metal–support interaction (SMSI), which enables the catalysts to have small metal size, high catalytic activity, and high stability. The strategy is demonstrated by successfully synthesizing ultrafine Co‐metal‐decorated 3D ordered macroporous titanium oxynitride (3DOM‐Co@TiOxNy). The 3DOM‐Co@TiOxNy catalyst exhibits comparable activities for oxygen reduction and evolution reactions, but much higher cycling stability than noble metals in alkaline conditions. The zinc–air battery using this catalyst delivers an excellent stability with less than 1% energy efficiency loss over 900 charge–discharge cycles at 20 mA cm−2. The high stability is attributed to the strong SMSI between Co and 3DOM‐TiOxNy which is verified by density functional theory calculations. This work sheds light on using OV‐rich semiconductors as a promising support to design efficient and durable nonprecious electrocatalysts. An oxygen vacancy (OV)‐rich semiconductor is introduced to design an efficient and durable nonprecious bifunctional oxygen electrocatalyst in alkaline conditions. The OVs promote the electrical conductivity of the oxide support, and at the same time offer a strong metal–support interaction, which gives small metal size, high catalytic activity, and stability. This is demonstrated by synthesizing ultrafine Co‐metal‐decorated 3D ordered macroporous titanium oxynitride.