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Nitrogen-enriched ordered mesoporous carbons through direct pyrolysis in ammonia with enhanced capacitive performance

2013; Royal Society of Chemistry; Volume: 1; Issue: 27 Linguagem: Inglês

10.1039/c3ta11342f

2050-7488

Xiqing Wang, Chenguang Liu, David Neff, Pasquale F. Fulvio, Richard T. Mayes, Aruna Zhamu, Qing Fang, Guorong Chen, Harry M. Meyer, Bor Z. Jang, Sheng Dai,

Mesoporous Materials and Catalysis

Self-assembly of phenolic resins and a Pluronic block copolymer via the soft-template method enables the formation of well-organized polymeric mesostructures, providing an easy way for preparation of ordered mesoporous carbons (OMCs). However, direct synthesis of OMCs with high nitrogen content remains a significant challenge due to the limited availability of nitrogen precursors capable of co-polymerizing with phenolic resins without deterioration of the order of mesostructural arrangement and significant diminishment of nitrogen content during carbonization. In this work, we demonstrate pyrolysis of the soft-templated polymeric composites in ammonia as a direct, facile way towards nitrogen-enriched OMCs (N-OMCs). This approach does not require any nitrogen-containing carbon precursors or post-treatment, but takes advantage of the preferential reaction and/or replacement of oxygen with nitrogen species, generated by decomposition of ammonia at elevated temperatures, in oxygen-rich polymers during pyrolysis. It combines carbonization, nitrogen functionalization, and activation into one simple process, generating N-OMCs with a uniform pore size, large surface area (up to 1400 m2 g−1), and high nitrogen content (up to 9.3 at%). More importantly, the ordering of the meso-structure is well-maintained as long as the heating temperature does not exceed 800 °C, above which (e.g., 850 °C) a slight structural degradation is observed. When being used as electrode materials for symmetric electric double layer capacitors, N-OMCs demonstrate enhanced capacitance (6.8 μF cm−2vs. 3.2 μF cm−2) and reduced ion diffusion resistance compared to the non-NH3-treated sample.