High-Performance Ir1/CeO2 Single-Atom Catalyst for the Oxidation of Toluene

The elimination of toluene is an obligatory target with increasing VOC emission in recent years. This study successfully prepared a single-atom Ir catalyst (Ir₁/CeO₂) by a simple incipient wetness impregnation method, confirmed by in situ CO DRIFTS and AC-HAADF-STEM. Compared to the cluster Ir catalyst (Ir/CeO₂-C), Ir₁/CeO₂ exhibited excellent catalytic performance, stability, and water resistance for the oxidation of toluene. By Raman, H₂-TPR, O₂-TPD, and XPS experiments, abundant oxygen defects and a unique Ir³⁺-Ov-Ce³⁺ structure were formed for the Ir₁/CeO₂ sample because it had a lower oxygen vacancy formation energy. Furthermore, the DFT results revealed that the Ir₁/CeO₂ sample had a lower ring-opening energy barrier and adsorption energy of the ring-opening products, which was the rate-determining step for the oxidation of toluene. This work provides instructive insights into the construction of Ir/CeO₂ catalysts for the highly efficient removal of VOCs.