Polyoxometalates Immobilized on Covalent Triazine Framework as Efficient Catalysts for Deep Oxidative Desulfurization

The immobilized polyoxometalates (POMs) with evenly dispersed catalytic sites, amphiphilic surface, and excellent recyclability are highly desired in many important reactions. Herein, PMo₁₂@CTF has been successfully fabricated by the electrostatic assembly of H₃PMo₁₂O₄₀ (PMo₁₂) with porous cationic covalent triazine framework (CTF), where PMo₁₂ are evenly dispersed on the support. The synthesized PMo₁₂@CTF is highly active for oxidative desulfurization of diesel fuel and dibenzothiophene (DBT) can be completely converted in 2 h under mild conditions (40 °C) in a biphasic system. Impressively, the catalytic activity of heterogeneous PMo₁₂@CTF (conversion: 100 %) is much higher than that of homogeneous PMo₁₂ (conversion: 20 %). The control experiments and contact angle measurements reveal that the CTF endows PMo₁₂@CTF with large surface area and amphiphilic feature and the catalyst can effectively contact with both oxidant H₂O₂ in extraction phase and DBT in oil phase. Moreover, PMo₁₂@CTF is robust and its catalytic activity is basically maintained after ten cycles.