Stabilizing Double Perovskite for Effective Bifunctional Oxygen Electrocatalysis in Alkaline Conditions
Stabilizing Double Perovskite for Effective Bifunctional Oxygen Electrocatalysis in Alkaline Conditions
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DOI：
10.1021/acs.chemmater.7b01114
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发表时间：
2017-08-08
影响因子：
8.6
通讯作者：
Luo, Jing-Li
中科院分区：
文献类型：
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作者：
Hua, Bin;Sun, Yi-Fei;Luo, Jing-Li
氧电催化是包括可逆燃料电池和金属-空气电池在内的新兴能量转换和存储设备的核心。然而，迄今为止，用经济可靠的替代品取代贵金属基氧还原反应（ORR）和析氧反应（OER）催化剂仍然具有挑战性。本文报道了一种阳离子有序的双钙钛矿氧化物，即PrBa0.85Ca0.15MnFeO5+delta，在OER和ORR中均具有优异的稳定性和活性。层状晶体结构提供了有序的氧空位通道和大量的表面氧缺陷，而适量的铁掺杂使b位阳离子保持在高氧化态，并具有最佳的e(g)填充。重要的是，DFT计算和先进的TEM分析验证了Ca在a位的掺入稳定了钙钛矿结构。这种双功能催化剂表现出与最先进的钙钛矿氧化物（如ba0.5 sr0.5 co0.8 fe0.2 2o3 -delta）相当的活性，同时表现出显著增强的鲁棒性。本研究为设计高效、稳健、经济的氧电催化钙钛矿氧化物提供了一种合理的方法，并揭示了晶体结构对催化性能的影响。
Oxygen electrocatalysis is at the heart of the emerging energy conversion and storage devices including reversible fuel cells and metal-air batteries. However, replacing the noble-metal-based oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) catalysts with affordable and robust alternatives remains challenging to date. Herein, we report a cation-ordered double perovskite oxide, i.e., PrBa0.85Ca0.15MnFeO5+delta, with excellent stability and activity in both OER and ORR The layered crystal structure provides ordered oxygen vacancy channels and a vast amount of surface oxygen defects, while the moderate amount of iron dopant keeps the B-site cations at high oxidation state with optimal e(g) fillings. Importantly, the DFT calculations along with the advanced TEM analysis verify that the incorporation of Ca at the A-site stabilizes the perovskite structure under potential bias. Such a bifunctional catalyst shows comparable, if not better, activity relative to the state-of-the-art perovskite oxides (e.g., Ba0.5Sr0.5Co0.8Fe0.2O3-delta) while demonstrating remarkably enhanced robustness. This work presents a rational approach of designing efficient, robust, and cost-effective perovskite oxide for oxygen electrocatalysis and sheds light on the influences of the crystallographic structure on the catalytic property.