Bi-functionality of samarium- and praseodymium-based perovskite catalysts for oxygen reduction and oxygen evolution reactions in alkaline medium

JOURNAL OF POWER SOURCES

卷:446

Article

Kolla, Praveen^1,2  Nasymov, Golibsho¹  Rajappagowda, Rudresh¹  Smirnova, Alevtina^1,2 

[1] South Dakota Sch Mines & Technol, Mat Engn & Sci Program, Rapid City, SD 57701 USA

[2] South Dakota Sch Mines & Technol, Chem & Appl Biol Sci Dept, Rapid City, SD 57701 USA

关键词: Praseodymium;    Samarium;    Perovskites;    Oxygen evolution reaction;    Oxygen reduction reaction;    Metal-air batteries;    Regenerative fuel cells;   

DOI  :  10.1016/j.jpowsour.2019.227234

来源: Elsevier

【 摘 要 】

The present study ellucidates bi-functional catalytic activity of the graphene-supported praseodymium (PrNixCo1-xO3-delta) and samarium (SmNixC1-xO3-delta) perovskites towards oxygen evolution and oxygen reduction reactions in alkaline solutions. The perovskites with varied Ni and Co content (of x = 0.1, 0.5, and 0.9) were synthesized via sol-gel glycine-nitrite combustion followed by heat-treated at 700, 900 and 1200 degrees C. The cubic perovskite phase of PrNixCo1-xO3-delta was stabilized at x = 0.1, 0.5 in the entire temperature range (of 700 degrees C-1200 degrees C), while the perovskite phase of SmNixCo1-xO3-delta (x = 0.1, 0.5) was observed only at lower temperatures (of 700 and 900 degrees C). Consequently, changes in structural properties resulted in superior oxygen evolution reaction (OER) electrochemical activity in comparison to the state-of-the-art IrO2. Among the Sm-based perovskites, SmNi0.1Co0.9O3-delta (700 degrees C) demonstrated OER mass activity of 495 mA/mg and the highest oxygen reduction reaction (ORR) activity of 95 mA/cm(2).mg. For Pr-based perovskites, the highest electrocatalytic activity toward OER and ORR was observed for PrNi0.1Co0.9O3-delta (900 degrees C) resulting in 60 mA/mg for ORR and 680 mA/mg for OER which is 50% higher than the mass activity of the state-of-the-art IrO2 catalyst. The overall performance of the composites is discussed in terms of graphene support interactions, Co and Ni redox processes, relative concentration of oxygen-vacancy sites and OER/ORR bi-functionality.

【 授权许可】

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