Fabrication of nitrogen doped and hierarchically porous carbon flowers for CO2 adsorption

Porous carbon with specifically designed structure as CO 2 adsorbent is a very attractive and interesting research topic. In this study, we presented the synthesis and CO 2 adsorption of flower shaped porous carbons. Flower-like hydrochar derived from the hydrothermal reaction of glucose, cobalt sulfate, and hexamethylenetetramine was used as the precursor, which was converted to carbon flower during CO 2 activation. The flowers had hierarchically macro-meso-microporous structure. Interspaces and voids were formed by assembly of the petals, and the petals were distributed with pores of different scales. The formation mechanism of, and influences of various synthesis parameters on the flower shape were studied and analyzed. The carbon flowers exhibited surface area of 422−691 m 2 /g, and very high nitrogen content of 9.31–11.91 wt%. CO 2 adsorption performances of the carbon flowers were also studied. Influences of the textural properties and doped nitrogen on the adsorption performances were investigated. The experiment results demonstrated that nitrogen doping showed positive effects on CO 2 uptake at 1 bar, and had strong influence on the CO 2 /N 2 selectivity.