Promotional effects of zirconium doped CeVO4 for the low-temperature selective catalytic reduction of NOx with NH3

Abstract

In this work, we developed a novel zirconium doped CeVO4 to form Ce1−xZrxVO4 (x=0.05, 0.10, 0.15, 0.20, 0.30, 0.50, 0.70, 0.80) solid solution as a low-temperature catalyst for the selective catalytic reduction (SCR) of NOx with NH3. The optimized catalysts showed excellent performance at low temperature. The light-off temperature (the temperature at which the conversion of NO reaches 50%) was down to about 125°C, while the temperature window (the NO conversion is above 80%) ranged from 150 to 375°C. The selectivity was kept close to 100% during the whole temperature range. Furthermore, the catalysts also exhibited good H2O/SO2 durability and fascinating performance at high gas hourly space velocity of 400,000h−1. Hydrogen temperature-programmed reduction, X-ray photoelectron spectroscopy, ammonia and nitrogen oxides temperature-programmed desorption and in-situ diffuse reflectance infrared Fourier transform experiments were performed to study the influence of Zr doping on the SCR performance. It was found that the introduction of Zr in CeVO4 with a proper amount could significantly increase the surface area, oxidative ability, active oxygen species and especially surface acid sites of the catalysts, which were beneficial to the promotion of SCR performance.