Photothermally Boosted CO2 Conversion by Silver Nanoparticles Anchored on a Bipyridinium Radical-Functionalized Covalent Triazine Framework.

Developing sustainable and energy-efficient catalytic systems for CO2 conversion is pivotal for advancing carbon cycle management, yet remains highly challenging. Here, we report a novel near-infrared (NIR) photothermal catalytic platform by depositing silver nanoparticles onto a bipyridinium radical-functionalized covalent triazine framework (CTF) for the carboxylative cyclization of propargylic amines with CO2 without external heating. It is found that, under 808 nm laser irradiation, the catalyst delivers a 6.9-fold enhancement in photothermal catalytic activity relative to its bipyridinium-free analogue. Due to the exceptional penetration depth of near-infrared light, this photothermal catalytic system achieves a record turnover frequency of 2952.1 h-1 even in the presence of translucent barriers. The stabilizing effect of extended π-conjugation within the CTF matrix on bipyridinium radicals maintains the high photothermal catalytic activity over 10 consecutive cycles. Furthermore, this photothermal catalytic system demonstrates practical scalability, allowing for gram-scale (∼10 g) one-pot synthesis of an oxazolidinone product under natural sunlight. This work not only provides a novel approach for promoting value-added CO2 conversion under mild conditions, but also demonstrates the transformative potential of bipyridinium radicals in designing high-performance NIR photothermal catalytic systems.