A direct template synthesis of nanoporous carbons with high mechanical stability using as-synthesized MCM-48 hostsElectronic supplementary information (ESI) available: Fig. S1: TEM images. Fig. S2: adsorption–desorption isotherms. Fig. S3: schematic for carbonization process. Fig. S4: TGA data. See http://www.rsc.org/suppdata/cc/b2/b202307p/