Dual Activation of Molecular NO and O 2 on a Pr-Doped CeO 2 -TiO 2 Catalyst for the Simultaneous Catalytic Purification of NO x and Toluene

Designing a bifunctional catalyst to concurrently activate NO and O 2 is of fundamental importance to the simultaneous catalytic removal of NO x and VOCs. During this process, sufficient electron transfer from the catalyst surface to the antibonding π* orbitals of adsorbed NO and O 2 is necessary to facilitate the adsorption and subsequent bond cleavage. Herein, an electronic orbital coupling strategy is applied by doping praseodymium (Pr) into a CeO 2 -TiO 2 (CeTi) composite oxide to obtain a PrCeTi bifunctional catalyst, which has a strong interaction with NO to form NO +, further splitting with N 3+ production and thereby enhancing NH 3 -SCR performance following the Langmuir–Hinshelwood mechanism. Meanwhile, O 2 adsorbs on the PrCeTi catalyst surface to produce superoxide (O 2 – ) and further transforms into peroxide (O 2 2– ) which, along with increased temperature, boosts the PhCH 3 total oxidation. Finally, the coactivation of NO and O 2 over the PrCeTi catalyst contributes to its better simultaneous removal efficiency of NO x and toluene than that of the CeTi catalyst.