Ammonia has emerged as a promising energy carrier owing to its carbon neutral content and low expense in long-range transportation. Therefore, development of a specific pathway to release the energy stored in ammonia is therefore in urgent demand. Electrochemical oxidation provides a convenient and reliable route to attain efficient utilization of ammonia. Here, we report that the high entropy (Mn, Fe, Co, Ni, Cu)₃O₄ oxides can achieve high electrocatalytic activity for ammonia oxidation reaction (AOR) in non-aqueous solutions. The AOR onset overpotential of (Mn, Fe, Co, Ni, Cu)₃O₄ is 0.70 V, which is nearly 0.2 V lower than that of their most active single metal cation counterpart. The mass spectroscopy study reveals that (Mn, Fe, Co, Ni, Cu)₃O₄ preferentially oxidizes ammonia to environmentally friendly diatomic nitrogen with a Faradic efficiency of over 85%. The X-ray photoelectron spectroscopy (XPS) result indicates that the balancing metal d-band of Mn and Cu cations helps retain a long-lasting electrocatalytic activity. Overall, this work introduces a new family of earth-abundant transition metal high entropy oxide electrocatalysts for AOR, thus heralding a new paradigm of catalyst design for enabling ammonia as an energy carrier.

由于其碳中性含量和远程运输成本低，氨已成为一种有前途的能源载体。因此，迫切需要开发一种特定途径来释放储存在氨中的能量。电化学氧化提供了一种方便可靠的途径来实现氨的有效利用。在这里，我们报告了高熵 (Mn、Fe、Co、Ni、Cu) ₃ O ₄氧化物可以在非水溶液中实现氨氧化反应 (AOR) 的高电催化活性。(Mn, Fe, Co, Ni, Cu) ₃ O ₄的AOR起始过电位为 0.70 V，比其最活跃的单金属阳离子对应物低近 0.2 V。质谱研究表明，(Mn, Fe, Co, Ni, Cu) ₃ O ₄优先将氨氧化为环境友好的双原子氮，法拉第效率超过85%。X 射线光电子能谱 (XPS) 结果表明，Mn 和 Cu 阳离子的平衡金属 d 带有助于保持持久的电催化活性。总的来说，这项工作为 AOR 引入了一个新的地球丰富的过渡金属高熵氧化物电催化剂家族，从而预示着一种新的催化剂设计范式，使氨作为能量载体。