Experiment and mechanism investigation on simultaneously catalytic reduction of NOx and oxidation of toluene over MnOx/Cu-SAPO-34

• The simultaneously catalytic abatement of NH 3 and toluene was investigated. • Simultaneous conversion of NO and toluene is ≥80% at 300°C-380°C . • Isolated Cu 2+ is protected from toluene poisoning by framework of Cu-SAPO-34. • Toluene oxidation follows MvK mechanism with lattice oxygen as active sites. • SCR simultaneously follows E-R and L-H mechanism at 150-350°C. Simultaneous catalytic abatement of NO x and VOCs is investigated with MnO x /Cu-SAPO-34 facilely synthesized as bifunctional catalyst. It is found that SAPO-34 framework provides selectivity for toluene and SCR reactants, enabling SCR and toluene oxidation to proceed simultaneously inside and outside SAPO-34, which avoids their mutual inhibition. Meanwhile, the higher loading of Mn, the stronger redox performance of catalyst. Correspondingly, the active temperature range for simultaneous removal of NO x and toluene shifts to lower temperature. Among them, the best simultaneous removal performance of NO x and toluene are ≥80% in 300°C-380°C with high CO 2 selectivity (∼100%) and N 2 selectivity (>80%) over 20%MnOx/SAPO-34. Furthermore, the simultaneous reaction mechanism is explored through a series of temperature programmed experiments. The toluene is oxidized to CO 2 and H 2 O by lattice oxygen of MnO x , while the decomposition of intermediates is a presumable rate-control step. The NO x is reduced by NH 3 or NH 4 + adsorbed on isolated Cu 2+ or Brønsted acid sites inside SAPO-34, which follows the E-R and L-H mechanism respectively. Moreover, there is obvious competitive effects on NH 3 adsorption by toluene, which further inhibits its oxidation and enhancing the N 2 selectivity at high temperature.