Tunable-quaternary (N, S, O, P)-doped porous carbon microspheres with ultramicropores for CO2 capture

The rational microstructure design and general synthesis of multiple heteroatoms co-doped carbon materials for effective and selective capture of CO2 is highly imperative in terms of mitigating CO2 emissions. Here, novel quaternary (N, S, O, P)-doped porous carbon microspheres with high surface area and large volume of ultra-micropores were prepared facilely for the first time through directly pyrolyzing an organic-inorganic hybrid polyphosphazene. Through adjusting the pyrolysis temperature (750-950 degrees C), the resultant carbon materials could possess variable surface area (342-653 m(2) g(-1)) and pore volume (0.17-0.32 cm(3) g(-1)), and a tunable content of heteroatoms including N, S, O and P distributed homogeneously in the carbon framework. As CO2 adsorbents, the heteroatoms quaternary-doped porous carbons show a significant amount of CO2 adsorption capacity at 760 mmHg, almost 3 mmol g(-1) at 25 degrees C and 4.3 mmol g(-1) at 0 degrees C, respectively. Also, the as-prepared sorbent exhibits good CO2/N-2 selectivity, high isosteric heat and stable cycling ability. The good CO2 capture performance could be ascribed to its high microporosity and multiple heteroatom doping in the carbon framework. When combined with the low cost of the polyphosphazene precursor, these features make the novel quaternary-doped carbon materials a promising adsorbent candidate for highly effective and selective capture of CO2.