Active site-directed tandem catalysis on CuO/V_O-MnO₂ for efficient and stable catalytic ozonation of S-VOCs under mild condition

Tandem catalysis can carry out the sequential coupling of multiple reactions in one operation, which is promising for sulfur-containing volatile organic compounds (S-VOCs) control. Herein, a tandem catalyst (CuO/V_O-MnO₂) consisting of well-dispersed CuO shell and oxygen vacancy-rich (V_O) hollow-structured MnO₂ core exhibited superior adsorption and catalytic performance under the mild condition for the elimination of CH₃SH. The optimum 5CuO/V_O-MnO₂ can reach a significant improvement in CH₃SH elimination of ∼99 % conversion over bare CuO/ pristine MnO₂ at 25 ℃ under a GHSV of 60,000 mL h⁻¹ g⁻¹, and an almost 4-fold enhanced catalytic activity of the individual O₃ with ∼99 % utilization of the applied O₃ in the feed gas. The underlying tandem catalytic mechanism was in-depth identified by XPS, in situ DRIFTs and high-level computational study. The secret to the superior performance of CuO/V_O-MnO₂ lies in that CH₃SH was preferentially chemisorbed on multivalent CuO (Cu(I)/Cu(II)), then deeply oxidized into final product of SO₄²⁻/CO₃²⁻ via the catalytic ozonation by multivalent CuO and oxygen vacancies of neighbouring V_O-MnO₂. Attributed to the efficient electron replenishing interaction and cycling of active oxygen vacancies at the tandem reactive site of CuO/V_O-MnO₂ interface ([tbnd]Mn(IV) + [tbnd]Cu(II) + 2O_latt → [tbnd]Mn(II)/Mn(III) + V_O + [tbnd]Cu(I) + O₂), its lifetime can extend to 300 min with limited loss of activity. These findings thus open up a way to address current multiple challenges in S-VOCs control using a single hierarchical core-shell structure with tandem catalysis.