Molten salt synthesis of nitrogen-doped porous carbons for hydrogen sulfide adsorptive removal

Nitrogen-doped porous carbons (NPCs) with high hydrogen sulfide (H2S) adsorption capacity have been prepared through the molten-salt approach, using d-glucose as carbon source, melamine as nitrogen source and eutectic salt (LiCl/KCl) as porogen. The NPCs possess tunable nitrogen content (3.07-24.31 wt.%) and specific surface area (451-1190 m2/g) with the changing of the weight ratio of nitrogen source to carbon source and synthesis temperature. The H2S adsorptive performance of NPCs is highly superior to that of non-doped porous carbon. X-rays photoelectron spectroscopy analyses combined with quantum chemical calculations demonstrate that the adsorption performance of the as-prepared NPCs depends on their nitrogen content and N-bonding configurations in the carbon materials, as well as their porosity. Pyridinic nitrogen doped carbon in NPCs have stronger interaction with H2S compared to pyrrolic and graphitic nitrogen doped carbon. Based on the advantages of the developed porosity and abundant nitrogen functional groups, the saturated sorption capacities of 0.97-1.25 mmol H2S/g can be achieved over NPCs at 25 °C under dry and anaerobic conditions.