Promotional effect of H3PO4 on ceria catalyst for selective catalytic reduction of NO by NH3

A series of H3PO4-modified CeO2 samples were prepared by impregnation of CeO2 with H3PO4 solution, and evaluated for the selective catalytic reduction of NOx by NH3. The samples were characterized by X-ray diffraction, N2 adsorption-desorption, infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, temperature-programmed desorption of NH3, and temperature-programmed reduction of H2. The results showed that more than 80% NO conversion was achieved in the temperature range 250–550 °C over the H3PO4-CeO2 catalyst. The enhanced catalytic performance could be ascribed to the increase in acidic strength, especially Brönsted acidity, and reduction in redox properties of the CeO2 after H3PO4 modification.

Graphical AbstractThe addition of H3PO4 on CeO2 increased the acidic strength and modified the redox ability, which could lead to a very broad operation temperature window of CeO2-based catalyst.Figure optionsDownload full-size imageDownload as PowerPoint slide