UV‐to‐NIR Harvesting Conjugated Porous Polymer Nanocomposite: Upconversion and Plasmon Expedited Thioether Photooxidation

Abstract Photocatalysts capable of harvesting a broad range of the solar spectrum are essential for sustainable chemical transformations and environmental remediation. Herein, we have integrated NIR‐absorbing upconversion nanoparticles (UCNP) with UV‐Vis absorbing conjugated porous organic polymer (POP) through the in situ multicomponent C−C coupling to fabricate a UC−POP nanocomposite. The light‐harvesting ability of UC−POP is further augmented by loading plasmonic gold nanoparticles (AuNP) into UC−POP. A three‐times enhancement in the upconversion luminescence is observed upon the incorporation of AuNP in UC−POP, subsequently boosting the photocatalytic activity of UC−POP−Au. The spectroscopic and photoelectrochemical investigations infer the enhanced photocatalytic oxidation of thioethers, including mustard gas simulant by UC−POP−Au compared to POP and UC−POP due to the facile electron‐hole pair generation, suppressed exciton recombination, and efficient charge carrier migration. Thus, the unique design strategy of combining plasmonic and upconversion nanoparticles with a conjugated porous organic polymer opens up new vistas towards artificial light harvesting.