High resolution N2 adsorption isotherms by graphitized carbon black and nongraphitized carbon black – αs-Curves, adsorption enthalpies and entropies

The high resolution N2 adsorption isotherms (77.4 K) by graphitized carbon blacks (GCB-I: ABET = 54.2 m2 g−1 and GCB-II: ABET = 69.4 m2 g−1) and nongraphitized carbon black (NGCB: ABET = 18.87 m2 g−1) have been measured at p/p° = 5 × 10−8–0.99. αs-Curve of the N2 adsorption isotherm by GCB-I is completely overlapped with that by GCB-II in the pressure range of p/p° = 5 × 10−6–0.90, but the N2αs-curve by GCB-I is remarkably different from that by NGCB. The standard N2αs-data by GCB-I and NGCB have been determined in the range of αs = 0.002–2.2. On the basis of the N2 adsorption isotherms at the two temperatures (77.4 K, 87.3 K), the isosteric heat of adsorption (differential adsorption enthalpies), the differential adsorption entropies, and the integral adsorption entropies of N2 molecules have been evaluated between θ (coverage) = 0.05 and θ = 1.50. The surface homogeneity/heterogeneity of carbon black samples has been discussed by the N2 differential adsorption enthalpies. The adsorbed state of N2 molecules on the carbon black surfaces has been considered by the differential and integral adsorption entropies.

αs-Curves of N2 by graphitized carbon black sample (GCB-I) and nongraphitized carbon black sample (NGCB) at 77.4 K.Figure optionsDownload high-quality image (90 K)Download as PowerPoint slideResearch highlights
► New αs-curve of N2 gas adsorption on nongraphitized and graphitized carbon black at 77 K.
► Adsorption enthalpies and entropies of N2 gas adsorption on carbon black.
► High resolution N2 adsorption isotherm on carbon black at 77.4 and 87.3 K.