Ionothermal template transformations for preparation of tubular porous nitrogen doped carbons
A facile approach for the Zn-free ionothermal synthesis of highly porous nitrogen doped carbons possessing tubular transport pores is demonstrated employing adenine as biomass derived precursor and surfactant together with calcium or magnesium chloride hydrates as combined solvent-porogens. The overall process can be regarded as a combination of liquid templating by means of sol–gel synthesis with hard templating via in situ transformation of the melt into solid fibrous salt crystals. The employment of MgCl2·6H2O results in tubular nitrogen doped carbons showing anisotropic porosity and very high specific surface areas up to 2780 m2 g−1 and total pore volumes up to 3.86 cm3 g−1. The formation of the tubular porosity can be connected to a cooperative effect between in situ formed, solid hydrate phases and their modulation with adenine and its polycondensation products. The combination of high SSA with the channel-like porosity generates a highly accessible structure making those carbon materials appealing for applications that demand good mass transport. The obtained materials were exemplarily employed as supercapacitor electrodes resulting in high specific capacitances up to 238 F g−1 at a low scan rate of 2 mV s−1 and up to 144 F g−1 at a high scan rate of 200 mV s−1.