Nanoporous carbons derived from MOFs as metal-free catalysts for selective aerobic oxidations†
Metal-free nanocarbon catalysts have attracted much attention in recent years for their advantages of corrosion resistance, no heavy metal pollution and environmental friendliness as compared to metal-based catalysts. However, a facile preparation of heteroatom doped mesoporous carbon with a high catalytic efficiency is challenging. Here we report the development of a new kind of metal-free catalyst comprised of highly graphitized N-doped nanoporous carbons from direct carbonization of metal–organic frameworks. After metal etching, large specific surface areas and pore volumes, as well as high contents of sp2-bonded carbons are realized in the obtained carbons at the same time. As metal-free catalysts, these nitrogen-doped carbon materials exhibit excellent catalytic performances and robust stability in a series of oxidation reactions including aerobic oxidation of cyclohexane and toluene as well as oxidative coupling of amines. Systematic characterizations suggest that the accessible mesopores generated by chemical etching, and the homogeneous distribution of doped graphitic-type nitrogen should be responsible for the unprecedented performance of these carbon catalysts.