Influence of doping nitrogen, sulfur, and phosphorus on activated carbons for gas adsorption of H2, CH4 and CO2

Hexagonally packed mesoporous silica (HMS) was used as a kind of template-like material to prepare heteroatom doped porous carbons from the polymerization reactions of resorcinol and formaldehyde in the HMS pore channels. Different acids (HNO3, H2SO4, H3PO4) were used to catalyze the polymerization reactions to obtain N-doped, S-doped, and P-doped porous carbons, respectively. The adsorption properties of H2, CH4, and CO2 were investigated on these doped carbon materials systematically. For the hydrogen adsorption, the adsorption amount was 11.8%, 21.1%, and 33.3% higher on N-doped, S-doped, and P-doped porous carbons, respectively, than the carbon sample without doping, and the highest hydrogen uptake reached 14.88 mmol g−1 on the P-doped sample; regarding the CO2 adsorption, the adsorption amount reached 3.60 mmol g−1 and 3.16 mmol g−1 on the S-doped sample and N-doped sample, respectively, which is 39.5% and 22.5% higher than the sample without doping; it also shows that methane uptake amount was significantly increased by 27.1% on the S-doped sample as compared to the sample without doping, i.e., 3.52 mmol g−1 of CH4. Therefore, it is predicted that these doped carbon materials with high specific surface area are of great potential for the gas adsorption of H2, CH4, and CO2.