Last modified: 2014-10-07
Abstract
The oxygen reduction reaction (ORR) is one of the important reactions not only in life process but also in artificial energy conversion systems, such as fuel cells and metal-air batteries. Due to the slow kinetics, ORR catalysts such as Pt-based materials are widely investigated, but how to prepare sustainable catalysts is still one long-term challenge.[1-5] Thanks to unique electronic interactions between the lone-pair electrons of nitrogen and the p-system of graphitic carbon, nitrogen (N)-doped carbon nanostructures are among the most promising noble-metal free catalysts for oxygen reduction reaction (ORR).[2-4] However, N-doped carbon for ORR is commonly prepared by the pyrolysis/annealing at high temperature up to 1100 oC. As chemists, we prefer controlling the chemical reactions as we like; however, in such high temperature, it is extremely difficult to control the reactions during the preparation of N-doped carbon. Therefore, development of ORR active N-doped carbon at low temperature is highly desired.
It was reported that the graphitization of carbon at high temperature in preparation of N-doped carbon was a key step for an effective ORR catalysts.[4] This suggests us why not use the graphitic carbon as a template directly to prepare N-doped carbon via a wet chemistry way. To verify this hypothesis, we report here that starting from a reactive carbon template and an N-containing molecule, the resultant N-doped carbon could be obtained via a mild wet chemical reaction; meanwhile, an impressive ORR catalytic activity was retained. Moreover, this strategy could be extended to further rational combination of, e.g., the reactive carbon template, N-containing molecules of different sizes and reactivity, transition metal-salts (e.g., Co, and Fe), and wet chemical reaction conditions, thus offering further potentialities. Contrary to the high-temperature route that is widely used, this proposal highlights the preparation of ORR active N-doped carbon from a reactive carbon template and an N-containing molecule via a wet chemical way.
References
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