Sulfone-Decorated Conjugated Organic Polymers Activate Oxygen for Photocatalytic Methane Conversion

Oxidizing CH₄ into liquid products with O₂ under mild conditions still mainly relies on metal catalysis. We prepared a series of sulfone-modified conjugated organic polymers and found that the catalyst with proper S^VI content (0.10) could drive O₂ →H₂ O₂ →⋅OH to oxidize CH₄ into CH₃ OH and HCOOH directly and efficiently at room temperature under light irradiation. Experimental results showed that after 4 h reaction, decomposition rate and residual amounts of H₂ O₂ were 81.21 % and 4.83 mmol g_cat ^-1 respectively, and CH₄ conversion rate was 22.81 %. Mechanism studies revealed that illumination could induce the homolytic dissociation of S=O bonds on catalyst to produce oxygen and sulfur radicals, where the ⋅O could adsorb and activate CH₄ , and the ⋅S could supply electrons for ¹ O₂ to generate H₂ O₂ and then for decomposing the H₂ O₂ into ⋅OH timely to oxidize CH₄ . This research provided a novel organic catalysis approach for oxygen activation and utilization.