Direct Heating Amino Acids with Silica: A Universal Solvent‐Free Assembly Approach to Highly Nitrogen‐Doped Mesoporous Carbon Materials

Abstract

A general solvent‐free assembly approach via directly heating amino acid and mesoporous silica mixtures is developed for the synthesis of a family of highly nitrogen‐doped mesoporous carbons. Amino acids have been used as the sole precursors for templating synthesis of a series of ordered mesoporous carbons. During heating, amino acids are melted and strongly interact with silica, leading to effective loading and improved carbon yields (up to ≈25 wt%), thus to successful structure replication and nitrogen‐doping. Unique solvent‐free structure assembly mechanisms are proposed and elucidated semi‐quantitatively by using two affinity scales. Significantly high nitrogen‐doping levels are achieved, up to 9.4 (16.0) wt% via carbonization at 900 (700) °C. The diverse types of amino acids, their variable interactions with silica and different pyrolytic behaviors lead to nitrogen‐doped mesoporous carbons with tunable surface areas (700–1400 m2 g−1), pore volumes (0.9–2.5 cm3 g−1), pore sizes (4.3–10 nm), and particle sizes from a single template. As demonstrations, the typical nitrogen‐doped carbons show good performance in CO2 capture with high CO2/N2 selectivities up to ≈48. Moreover, they show attractive performance for oxygen reduction reaction, with an onset and a half‐wave potential of ≈−0.06 and −0.14 V (vs Ag/AgCl).