ORIGINAL PAPER Sponge-like carbon containing nitrogen and iron provides a non-precious oxygen reduction catalyst Hui Wang & Wei Wang & Julian Key & Shan Ji & Yuanyuan Ma & Lindiwe Khotseng & Weizhong Lv & Rongfang Wang Received: 8 October 2014 /Revised: 16 December 2014 /Accepted: 17 December 2014 # Springer-Verlag Berlin Heidelberg 2015 Abstract Sponge-like nitrogen-containing carbon (SNC) was synthesized via a template-free approach through pyrolyzing a mixture of bipyridine and iron (III) chloride. Transmission electron microscopy revealed that the prepared SNC com- prised an interconnected highly porous three-dimensional framework. Using rotating disk electrode measurements to measure oxygen reduction activity and methanol tolerance, SNC was found to have a 22.2 mV more negative half-wave potential than that of commercial Pt/C and strong methanol tolerance. We conclude that SNC affords a promising “non- precious” oxygen reduction catalyst in alkaline medium. Keywords Sponge-like . Nitrogen-containing carbon . Electrocatalyst . Oxygen reduction reaction Introduction Fuel cells efficiently convert chemical energy to electricity via electrocatalytic reactions occurring on the cathode and anode [1–3]. However, the slow kinetics of the oxygen reduction reaction (ORR) on the cathode remains a primary factor hindering fuel cell commercialization [4, 5]. Currently, nano- sized platinum (Pt) and platinum-based catalysts are used as ORR catalysts, but their prohibitive cost, scarcity, and even- tual decline in catalytic activity are unsuitable for large-scale applications [6]. Electrocatalysts based on non-precious metals offer a promising alternative to replace expensive Pt- based catalysts. ORR catalysts based on nitrogen-containing carbon mate- rials offer low cost, long durability, and are environmental friendly [7–9]. Recently, N-doped carboneous nanomaterials and materials containing Fe have proved promising [10–13], but due to a low density of catalytic active sites, their ORR performance is lower than that of commercial Pt/C [14]. However, the ORR performance of the carbon materials can be significantly improved by increasing their surface area and porosity [15, 16], and through obtaining specific morphol- ogies and nanostructures: e.g., in Fe–N-doped carbon-based materials such as iron encapsulated within pod-like carbon nanotubes [ 17], mesoporous carbon-supported Fe-N x electrocatalysts [18, 19], and N-enriched core–shell structured Fe/Fe 3 C-C nanorods [20]. Liao et al. prepared nitrogen- containing carbon nanotube arrays by chemical vapor deposi- tion using ferrocene as the catalyst and imidazole as the source of carbon and nitrogen [13]. Wang et al. [5] synthesized an efficient ORR electrocatalyst, Fe 2 N–N-doped graphitic nanocarbon, through an ion-exchanged route. However, the synthesis procedures are either complicated or signif- icantly cause deterioration of the carbon material’ s active sites [15, 21]. In the present study, nitrogen-containing carbon with po- rous spongy-like structure was synthesized by a template-free approach in which 2,2-bipyridine provided a source of carbon with a high nitrogen content. The resultant sponge-like nitro- gen-containing carbon (SNC) had electrocatalytic ORR activ- ity comparable to that of commercial Pt/C and had consider- ably higher methanol tolerance. H. Wang : W. Wang : Y. Ma : R. Wang (*) College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070, China e-mail: wrf38745779@126.com J. Key : S. Ji (*) : L. Khotseng South African Institute for Advanced Materials Chemistry, University of the Western Cape, Private Bag X17, Bellville 7535, Cape Town, South Africa e-mail: sji@uwc.ac.za W. Lv College of Chemistry and Chemical Engineering, Shenzhen University, Shenzhen 518060, China J Solid State Electrochem DOI 10.1007/s10008-014-2719-1