Refining Carbon Pore Size Analysis by Using Adsorption Data of Multiple Gases at Various Temperatures and 2D-NLDFT Modeling

摘要

The pore size distribution (PSD) of porous carbons is usually calculated from standard adsorption isotherms of N2 or Ar measured at their boiling points, 77 or 87 K, It is well known, however, that carbon samples that contain very fine micropores are difficult to analyze at cryogenic temperatures due to extremely slow diffusion at low relative pressures. As early as in 1982, Rodriguez-Reinoso et aL [1] reported that measurements of N2 adsorption isotherms at 77 K on some carbons with fine pores of molecular sizes required more than 100 hours for completion Increasing measurement temperature to 90 K dramatically reduced equilibration time and improved accuracy of measured data.