Sorption and electrochemical properties of carbon–silica composites and carbons from 2,3-dihydroxynaphthalene

Abstract

Carbon–silica composites were obtained by uniformly coating the entire pore surface of SBA-15 and KIT-6 with a thin carbon layer using a 2,3-dihydroxynaphthalene as a carbon source. Due to formation of uniform carbon coating obtained composites possesses electrical conductivity despite the insulative nature of the silicas and thus exhibit ohmic curves. The specific capacitance per surface area of carbon–silica composites is higher than those of conventional activated carbons due to carbon–silica composites exhibited capacitance from electric double-layer and a time-consuming process between carbon surface and H2SO4 electrolyte similar to pseudocapacitance. This allows considering such composites as electrode materials with uniform pores. The Hydrogen initial potential for adsorption |Δµ 0| and density of pore surface filling with hydrogen for the composite with higher carbon content (24.7 µg/m2) is more than 5 times higher than for the initial silica (4.6 µg/m2) and approximately 2 times higher than for the composite with lower carbon content (10.4 µg/m2). |Δµ 0| for the obtained porous carbons is higher (5.2 kJ/mol) than for the initial matrices (2.8 kJ/mol) and carbon–silica composites (3.7–5.1 kJ/mol).