Solvent Effects on the Low-Temperature NH3-SCR Activity and Hydrothermal Stability of WO3/SiO2@CeZrOx Catalyst

Low-temperature NH3-SCR activity and high-temperature hydrothermal stability have always been recognized as two great challenges in the current developments of candidate NH3-SCR catalysts for practical applications. Herein, we present an optimizing solvent effects strategy to fabricate a WO3/SiO2@CeZrOx catalyst with highly dispersed SiO2 (W/Si@CeZr-m, prepared with the mixed solvent of deionized water and n-hexane). Compared with WO3/SiO2@CeZrOx catalysts prepared with single deionized water (W/Si@CeZr-w) and n-hexane (W/Si@CeZr-h), W/Si@CeZr-m not only shows highly effective NH3-SCR activity, especially at low temperatures (the complete conversion temperature being lowered 40 degrees C) but also exhibits a long lifetime (compares well with 84 000 miles). Optimizing solvent in the synthesis process of catalysts can enhance the electronic interaction of Si, W, and Ce, thus improving the amount of active sites and redox property of the catalysts. Moreover, the highly dispersed SiO2 can strengthen structural stability of W/Si@CeZr-m catalyst to resist hydrothermally aged. This work provides a simple route to prepare a highly effective candidate NH3-SCR catalyst for future applications in eliminating diesel engine exhausts.