Surface Area Determination of Porous Materials Using the Brunauer–Emmett–Teller (BET) Method: Limitations and Improvements

Abstract

Surface areas of metal−organic frameworks (MOFs) have been commonly characterized using the Brunauer−Emmett−Teller (BET) method based on adsorption isotherms of nonreactive nitrogen or argon. Recently, some discrepancies between surface areas computed from the BET method and those from geometric methods were reported in the literature. In this study, we systematically evaluated the BET and geometric surface areas of over 200 geometrically diverse real MOFs as well as CNTs with varying pore sizes as model systems to achieve a comprehensive understanding of the limitations of the BET and geometric methods. We compared the BET and geometric surface areas to the true monolayer area, which is determined by directly counting the number of molecules included in the monolayer of the surface from molecular simulation snapshots. Furthermore, we found that the excess sorption work (ESW) method or a combination of ESW and BET methods can potentially help facilitate a more accurate estimation of the surface area, particularly in cases where the structures show relatively less complex isotherms having distinct steps.

Syngas production by bi-reforming methane on an Ni–K-promoted catalyst using hydrotalcites and filamentous carbon as a support material

“…Textural characterization of the fresh materials was carried out by physical adsorption of N 2 at À196 C using a Quantachrome Autosorb-1 instrument. The apparent surface area of the catalyst and supporting material, S BET , was determined by applying the BET equation, 36 while the BJH method 37 was applied the desorption branch of the N 2 isotherms to obtain the average pore diameter (d pore ).…”

Optimising pyrolysis conditions for high-quality biochar production using black soldier fly larvae faecal-derived residue as feedstock

“…Physisorption isotherms were plotted based on nitrogen adsorption at increasing pressure using the Barret, Joyner and Balenda (BJH) method. This method is used to determine mesopore size distribution (Barrett et al, 1951;Sing, 2001;Sinha et al, 2019).…”

Biochar Type, Ratio, and Nutrient Levels in Growing Media Affects Seedling Production and Plant Performance

“…Barium Chloride was substituted for Calcium Chloride at the same concentration, in order to determine Ca in the extract. The surface area determined with the Brunauer, Emmett, and Teller method [48]. Peat physicochemical characteristics have been reported previously [10].…”