Type A and B gelatin as precursors of silica-templated porous carbon with a specified number of nitrogen- and oxygen-containing functionalities

Novel mesoporous carbons were synthesized using a hydrogel-based silica templating approach with control of the pH by ammonia buffer and gelatin as a promising carbon precursor. Three types of gelatin were selected: bovine-derived gelatin characterized by isoelectric point (IEP) of 4.5-5.0 and two porcine-derived ones with IEP of 7.0-9.0 and 8.5 +/- 0.5, respectively. The physicochemical properties of the obtained carbons were studied by low-temperature adsorption of nitrogen, elemental analysis, thermal analysis, and X-ray photoelectron spectroscopy. The role of the IEP of gelatin and the pH of synthesis in the gelatin-silica composite formation was investigated. The gelatin precipitates at the pH close to IEP, leading to lowered porosity of the obtained carbons. The carbon with the highest total pore volume (V-t = 4.91 cm(3)/g) was obtained using the composite prepared at a pH, which substantially exceeded the IEP. The nitrogen content for this sample reached 10.9 wt%. This carbon is characterized with a better ability to accumulate charge within the electrical double layer in 1 M H2SO4 and high capacitance retention of 95%. The content of N and O in the composites and carbons could be tuned by controlling the type of gelatin, the pH of synthesis, and the carbonization temperature.