Co9S8-porous carbon spheres as bifunctional electrocatalysts with high activity and stability for oxygen reduction and evolution reactions. (1st March 2018)

• Record Type: Journal Article
• Authors: Li, Wanqing; Li, Yuhang; Wang, Hongjuan; Cao, Yonghai; Yu, Hao; Peng, Feng
• Is Part Of: Electrochimica acta. Volume 265(2018)
• Page Start: 32
• Page End: 40
• Publication Date: 2018-03-01
• Subjects: Oxygen reduction reaction -- Oxygen evolution reaction -- Electrocatalysts -- Non-noble metal catalyst -- Cobalt sulfide; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2018.01.095
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: The oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) of multi-electron transfer are footstone and crucial reactions for energy conversion and storage technologies. The catalysts play the important roles in both ORR and OER. It is particularly desirable but difficult to use cheap raw materials and facile way to prepare non-noble metal bifunctional electrocatalysts with high activity and stability for both ORR and OER. Here, a simple and effective method is reported for synthesizing cobalt sulfide (Co9 S8 )-porous carbon spheres composite catalyst (Co9 S8 /CS) with thiourea, glucose and cobalt nitrate. The material structures of N, S co-doped carbon combined with Co9 S8 have been evidenced by high-resolution transmission electron microscopy, X-ray diffraction, Raman spectroscopy and X-ray photoelectron spectroscopy. Under the thermal treatment temperature of 800 °C, the prepared catalyst exhibits an analogous oxygen reduction dynamics behavior to the commercial platinum catalyst with a four-electron pathway, and a superior oxygen evolution performance with the small reversible potential gap of 0.78 V (ΔE = E j =10 – E1/2 ) to most of the bifunctional electrocatalysts reported to date, such as metal-free carbon hybrids and transition metal doped carbon materials. Due to the interaction between Co9 S8 and N, S co-doping carbon, Co9 S8 /CS-800 exhibits exceptionally good durability and excellent activity compared with the commercial Pt/C for ORR and OER, predicting a promising application in metal-air batteries and fuel cells. Graphical abstract: Image 1 Highlights: A cheap method is reported for synthesizing Co9 S8 -porous carbon spheres (Co9 S8 /CS). Co9 S8 /CS exhibits an analogous oxygen reduction dynamics behavior to Pt/C. Co9 S8 /CS shows a superior O2 evolution activity with small reversible potential gap. Co9 S8 /CS-800 exhibits exceptionally good durability for O2 reduction and evolution.