selective catalytic reduction

ceo sub

nh scr

selective catalytic

catalytic reduction

nh sub

catalysts_56358

reduction scr

mnox

Chemical Engineering Journal

MnO 2 is effective to selectively catalytically reduce NO (SCR) at low-temperature as an environmental catalyst, but suffers seriously from SO 2 poisoning. The α-MnO 2 @CeO 2 catalyst with a core-shell-like structure was synthesized by a two-step hydrothermal method. The CeO 2 shell with a depth of 10 nm was deposited outside α-MnO 2 , consisting of CeO 2 nanoparticles with a diameter of less than 5 nm. The ultra-thin CeO 2 shell was porous and did not affect the gaseous molecules diffusing. Furthermore, the valence of Mn decreased and the redox property improved due to the CeO 2 shell, thus increasing the NO removal efficiency. Moreover, CeO 2 shell could bind SO 2 strongly in priority to the poisoning of MnO 2 , thus functioning as the sacrifice to protect the α-MnO 2 core from SO 2 poisoning. The preferential adsorption of SO 2 on the CeO 2 shell was because of its strong covalent binding with SO 2 . SO 2 was oxidized and solidified by lattice oxygen, leaving the gas phase and avoiding further attack on active center Mn. This work offers a new route for the design of SO 2 -resistant Mn-based catalysts for SCR of NO x at low temperatures.

Core-shell-like structured α-MnO2@CeO2 catalyst for selective catalytic reduction of NO: Promoted activity and SO2 tolerance