Asap 2020

N₂ sorption analysis was carried out at −196 °C using an ASAP 2020 from Micromeritics on unloaded and loaded samples. The samples were degassed at a vacuum lower than 10 μm Hg at 130 °C for 6 h. The specific surface area (SSA) was calculated using the multipoint BET method [25 (link)], while the pore size distribution was calculated based on the density functional theory (DFT) method using the model for N₂ at −196 °C for slit-shaped pores. The total pore volume was obtained from single-point adsorption at a relative pressure P/P₀ ≈ 1. These calculations were all performed using ASAP 2020 (Micromeritics) software.

Nitrogen adsorption and desorption isotherms were measured at 77 K on a Micromeritics ASAP 2020 volumetric adsorption system. The total surface area and micropore volume were determined using the BET equation and the method of Dubinin-Radushkevich, respectively. The total volume V_{por total N2} was calculated by the single point method at a relative pressure of 0.97 from the nitrogen adsorption isotherms. The pore size distribution was obtained from the adsorption branch of the nitrogen isotherm using the density functional theory (DFT, slit pores).
Carbon dioxide adsorption isotherms were measured at 273 K on a Micromeritics ASAP 2020 volumetric adsorption system in the pressure range up to 0.1 MPa, (corresponding to a relative pressure of p/p₀ = 0.03).
The total volume V_{por total H2O} was obtained by a complete infiltration of the carbons with water in a vacuum (about 15 min) and subsequent weighing.
The macropore system of the carbons was investigated via mercury intrusion in the device Poremaster from Quantachrome. These measurements were done at the Institute for Technical Chemistry of the Leipzig University by the working group of D. Enke.
SEM photographs were taken on a FEI Nova Nanolab 200 (Portland, OR, USA) (accelerating voltage 10 kV) using a secondary electron detector. These measurements were done by the working group of Dirk Enke at Leipzig University.