Fabrication of ultra-large mesoporous carbon with tunable pore size by monodisperse silica particles derived from seed growth process

Monodisperse silica particles with tunable diameter from 16.8 nm to 39 nm were facilely prepared through the multi-step hydrolysis and condensation of tetraethylorthosilicate in aqueous solution of ammonia. The diameter of the final silica was controlled by the amount of tetraethylorthosilicate added in the subsequent seed growth. The silica particles with different diameter were used as template for the generation of ultra-large mesoporous carbon. The influence of silica particle diameter, sucrose/silica molar ratio and the silica template sintering on the final carbon structure was investigated by thermogravimetric analysis, transmission electron microscope and nitrogen adsorption at 77 K. When SiO2 particles with diameter varied from 16.8 nm to 39 nm were used as template, ultra-large porous carbon with narrow pore size distribution centered at 12.4 nm to 34.5 nm was achieved. When the sucrose/silica molar ratio increased from 0.044 to 0.18, the BET surface area of carbon decreased from 1579 m2/g to 1055 m2/g and pore volume decreased from 5.64 cm3/g to 2.50 cm3/g. High sucrose/silica molar ratio favors the generation of carbon with fewer defects, lower BET surface area and lower pore volume. The SiO2 template sintered at 900 °C leads to the aggregation of most SiO2 particles into larger spindly particles, which increases the window size of carbon and broadens the final pore size distribution.