Traditional earth-abundant coal as new energy materials to catalyze the oxygen reduction reaction in alkaline solution. (1st September 2016)

• Record Type: Journal Article
• Authors: Chen, Xingxing; Huang, Xinning; Wang, Tao; Barwe, Stefan; Xie, Kunpeng; Kayran, Yasin Ugur; Wintrich, Daniela; Schuhmann, Wolfgang; Masa, Justus
• Is Part Of: Electrochimica acta. Volume 211(2016)
• Page Start: 568
• Page End: 575
• Publication Date: 2016-09-01
• Subjects: oxygen reduction reaction -- coal -- N-doping -- fuel cells -- carbon materials; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2016.05.137
• Languages: English
• ISSNs: 0013-4686

Abstract

Highlights: Traditional coal is used to develop catalysts for the oxygen reduction reaction (ORR) in fuel cells as green energy conversion systems. The influence of pretreatment of the coal with various acids prior to modification with nitrogen and Fe has been carefully studied. The prepared catalysts show very promising ORR performance in alkaline electrolytes. The catalysts exhibit predominantly 4-electron reduction O2 to water Abstract: Coal is an earth-abundant energy resource, however, its direct combustion results in serious environmental pollution. Therefore, it becomes important to design value-added products from coal and to maximize its value chain. Herein, brown coal was used to develop non-precious metal catalysts for the oxygen reduction reaction (ORR) in fuel cells as green energy conversion systems. The brown coal was first pretreated with different acids, followed by N-doping at 800 °C in a stream of NH3 . A trace amount of Fe was further added to improve the electrocatalytic performance of the prepared catalyst towards ORR. The prepared coal-derived N-doped carbon further modified with 0.5% Fe exhibited onset potential of 0.92 V vs. RHE at a current density of −0.1 mA cm −2 and a predominantly 4-electron transfer pathway of oxygen to water in 0.1 M NaOH, which was evaluated by RDE and RRDE. The prepared electrocatalysts were further characterized by elemental analysis, XRD, Raman and XPS. The results suggest that the coal-derived ORR catalyst have convoluted graphitic and amorphous carbon structures. The N-content increased after acid-pretreatment and subsequent functionalization with nitrogen, while it slightly decreased after Fe incorporation apparently due to coordination of Fe with N. ORR activity enhancement after the incorporation of Fe is expected to mainly arise from a synergetic effect involving the interaction of Fe with N groups distributed in the carbon matrix.