Solvent-Free Self-Assembly to Ordered Mesoporous Poly (Pyridine@Schiff base) Catalysts for Efficient Upcycling of Waste Gaseous Sulfides from Natural Gas.

Transformation of volatile sulfides of carbonyl sulfide (COS) and hydrogen sulfide (H2S) into polysulfur from natural gas is the optimal route for their deep elimination and upcycling. Traditional catalysts show either poor sulfur-resistance or unsatisfactory polysulfur transportation. Here an ordered mesoporous pyridine@Schiff base designed from solidothermal-molten self-assembly of triblock copolymer template (Pluronic F127) with 2,6-diaminopyridine (DAP) monomer and terephthalaldehyde crosslinker is reported, which breaks the dominance of the resol route for nitrogen-doped, ordered mesoporous polymer design. Strong hydrogen-bond interaction between DAP and F127 ensures ordered mesoporosity formation, and condensation between DAP and phthalaldehyde yields poly(pyridine@Schiff base) framework. The resulting ordered mesoporous polymer and its derived ordered mesoporous carbon (RN-OMC) possess record-high nitrogen content and barrier-free mesochannels. These structural features afford long-term, continuous operation for the tandem conversion of COS and H2S to polysulfur (Sx). Under simulated natural gas conditions, the RN-OMC achieves ≈100% conversion and selectivity, and it compares favorably with literature-reported catalysts in the field.