Support effect of the supported ceria-based catalysts during NH3-SCR reaction

Abstract

To investigate how the physicochemical properties and NH3-selective catalytic reduction (NH3-SCR) performance of supported ceria-based catalysts are influenced as a function of support type, a series of CeO2/SiO2, CeO2/γ-Al2O3, CeO2/ZrO2, and CeO2/TiO2 catalysts were prepared. The physicochemical properties were probed by means of X-ray diffraction, Raman spectroscopy, Brunauer-Emmett-Teller surface area measurements, X-ray photoelectron spectroscopy, H2-temperature programmed reduction, and NH3-temperature programmed desorption. Furthermore, the supported ceria-based catalysts' catalytic performance and H2O + SO2 tolerance were evaluated by the NH3-SCR model reaction. The results indicate that out of the supported ceria-based catalysts studied, the CeO2/γ-Al2O3 catalyst exhibits the highest catalytic activity as a result of having a high relative Ce3+/Ce4+ ratio, optimum reduction behavior, and the largest total acid site concentration. Finally, the CeO2/γ-Al2O3 catalyst also presents excellent H2O + SO2 tolerance during the NH3-SCR process.