Ordered mesoporous TiO2/SBA-15 confined CexWy catalysts for selective catalytic reduction of NO using NH3

Abstract

Constructing Ce-based catalysts with excellent catalytic activity and toxicity resistance is an effective strategy for the selective catalytic reduction of NO by NH₃. Here, ordered mesoporous structured Ce_xW_y/TiO₂/SBA-15(TS) catalysts with different Ti/Si molar ratios (2 : 6, 3 : 6, 4 : 6) as well as the Ce and W contents were prepared using the vacuum impregnation method. Among them, the prepared TS-3 (Ti : Si = 3 : 6) carrier had a regular ordered mesoporous structure, which could provide a better supporting space for the attachment of active ingredients. After the active species were introduced, with the help of a series of characterization analyses, it was found that the Ce₁₀W₂/TS-3 catalyst had a large specific surface area, where the active species were stably dispersed via the pore confinement effect of the ordered mesopores’ structure, and the efficient charge transfer significantly enhanced its redox ability and surface acidity. In addition, the ordered pore structure protected the active sites from the competitive adsorption of water vapor and sulfur attack. Consequentially, the ordered mesoporous confined Ce₁₀W₂/TS-3 catalyst exhibited good catalytic performance in a wide temperature window, and its water and sulfur resistance was also enhanced to some extent. This work provided new insights into the design and synthesis of ordered mesoporous confined structure Ce-based catalysts for NH₃-SCR applications.