High entropy spinel oxide for efficient electrochemical oxidation of ammonia
High entropy spinel oxide for efficient electrochemical oxidation of ammonia
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DOI：
10.1007/s12274-021-3665-8
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发表时间：
2021-07-01
期刊：
影响因子：
9.9
通讯作者：
Liu, Jie
中科院分区：
文献类型：
--
作者：
He, Shi;Somayaji, Vasishta;Liu, Jie
氨因其碳中性含量高、长距离运输费用低而成为一种很有前途的能源载体。因此，迫切需要开发一种特定的途径来释放储存在氨中的能量。电化学氧化为实现氨的高效利用提供了一条方便可靠的途径。在这里，我们报道了高熵（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，比它们最活跃的单金属阳离子低近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，其法拉迪效率超过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，从而预示着一个新的催化剂设计范例，使氨作为能量载体。
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)(3)O-4 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)(3)O-4 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)(3)O-4 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.