Revealing active species of CePO4 catalyst for selective catalytic reduction of NOx with NH3

Revealing the active species of the catalyst is conducive to the design of more efficient catalyst. Herein, we tried to demonstrate the roles of amorphous and crystalline structures on CePO 4 catalyst during selective catalytic reduction (SCR) of NO x by NH 3 . Higher calcination temperature promotes the transfer of amorphous structure to crystalline structure on the surface of CePO 4 . Both amorphous and crystalline CePO 4 species on CePO- X samples can provide acid sites for NH 3 adsorption, but the former can provide more acid sites. The superior redox property of surface amorphous CePO 4 species contributes to its high NH 3 -SCR activity at low temperature, but it also leads to the decrease of high temperature (>350 °C) NH 3 -SCR activity due to the oxidation of NH 3 . In contrast, crystalline CePO 4 species shows high activity only at high temperature because of its poor redox property. Therefore, it can be inferred that amorphous and crystalline structures on CePO 4 catalyst can be the efficient active species of NH 3 -SCR at low and high temperature, respectively.