The rapid and effective transfer of chemical reactants to solid surfaces through a mesoporous structure is essential for enhancing the catalytic performance of nanomaterials. Such materials are essential for realizing durable, nonprecious-metal-based bifunctional electrocatalysts for rechargeable Zn–air batteries. Herein, highly reactant-accessible and mesoporous ZnMn₂O₄ nanospheres have been prepared via solvothermal synthesis. The nanospheres demonstrate excellent catalytic activity toward the oxygen reduction reaction and the oxygen evolution reaction in an aqueous alkaline solution. Moreover, compared with commercial 20 wt % platinum on carbon black, IrO₂, and RuO₂, the mesoporous ZnMn₂O₄ catalyst exhibits lower charge–discharge voltage gaps, good cycling stability, and improved round-trip efficiency. The enhanced electrochemical performance of the developed catalyst is attributed to the high specific surface area, numerous reaction sites by defective O₂^– (O_ads) species, and sufficient structural stability of the ZnMn₂O₄ material. The achievements presented in this work are of great importance for the development of outstanding non-noble spinel electrocatalysts for Zn–air batteries.

中文翻译：

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介孔ZnMn ₂ O ₄纳米球作为一种非贵重的锌-空气电池双功能催化剂

化学反应物通过中孔结构快速有效地转移到固体表面上对于增强纳米材料的催化性能至关重要。此类材料对于实现可充电的Zn-空气电池的耐用，非贵金属基双功能电催化剂至关重要。在此，已经通过溶剂热合成制备了高度可接近反应物的介孔ZnMn ₂ O ₄纳米球。纳米球对碱性水溶液中的氧还原反应和氧释放反应表现出优异的催化活性。另外，与市售的20重量％的炭黑，IrO ₂和RuO ₂上的铂相比，介孔ZnMn ₂ O ₄催化剂显示出较低的充放电电压间隙，良好的循环稳定性和改善的往返效率。发达的催化剂的增强的电化学性能归因于高的比表面积，由瑕疵的O众多反应位点₂ ^-（O_广告）的物种，以及足够的结构的ZnMn的稳定性₂ ö ₄材料。这项工作中取得的成就对于开发出色的锌-空气电池非贵金属尖晶石电催化剂具有重要意义。