Surface structural and energetic heterogeneity of carbon materials prepared from corn grains using steam and H₃PO₄‐steam activations

Abstract

The porous activated carbons (ACs) were prepared from corn grains through physical (steam) and chemical-physical (H 3 PO 4 -steam) activations. The effects of steam activation temperature (700-900°C) on pore development, surface roughness, and energetic heterogeneity were investigated in both activations. Also, the effect of prior carbonization on H 3 PO 4 -steam activation was studied. The physical properties, surface fractal dimensions, and adsorption energy distributions of ACs were determined from nitrogen adsorption-desorption isotherm data. Both physical and chemical-physical activations show that the AC with higher surface area, relatively smoother surface, and energetically heterogeneous surface could be produced at a maximum steam activation temperature (900°C).

Influence of chemical composition, porosity and fractal dimension on the electrical conductivity of carbon blacks

“…Fractal dimension is commonly employed as a roughness rate or an irregularity index of the material surface. Lately, diverse scientists described activated carbon fractal dimension [23,24,25,26,27,28,29]. In this study, fractal dimension was calculated applying the Frenkel-Halsey-Hill (FHH) equation [26], to the adsorption isotherm of N 2 (g) [25,27]:…”

“…Other researchers [13,20,23,50,51] have previously pointed out the connection between electrical conductivity and porosity. However, conductivity depends on different parameters (porosity, surface groups, structure etc.)…”