Titanium carbide derived nanoporous carbon for energy-related applications

摘要

High surface area nanoporous carbon has been prepared by thermo-chemical etching of titanium carbide TiC in chlorine in the temperature range 200-1200 deg C. Structural analysis showed that this carbide-derived carbon (CDC) was highly disordered at all synthesis temperatures. Higher temperature resulted in increasing ordering and formation of bent graphene sheets or thin graphitic ribbons. Soft X-ray absorption near-edge structure spectroscopy demonstrated that CDC consisted mostly of sp2 bonded carbon. Small-angle X-ray scattering and argon sorption measurements showed that the uniform carbon-carbon distance in cubic TiC resulted in the formation of small pores with a narrow size distribution at low synthesis temperatures; synthesis temperatures above 800 deg C resulted in larger pores. CDC produced at 600-800 deg C show great potential for energy-related applications. Hydrogen sorption experiments at -195.8 deg C and atmospheric pressure showed a maximum gravimetric capacity of approx 330 cm~3/g (3.0 wt. percent). Methane sorption at 25 deg C demonstrated a maximum capacity above 46 cm~3/g (45 vol/vol or 3.1 wt. percent) at atmospheric pressure. When tested as electrodes for supercapacitors with an organic electrolyte, the hydrogen-treated CDC showed specific capacitance up to 130 F/g with no degradation after 10000 cycles.