One-pot synthesis of highly dispersed mesoporous Cu/ZrO2 catalysts for NH3-SCR

Abstract

Catalysts consisting of highly dispersed copper on a mesoporous ZrO2 support were synthesised via a one-pot sol-gel synthesis and were tested for the selective catalytic reduction of NOx by NH3. The copper dispersion was investigated by XRD and TEM, which showed no discernible copper oxide particles up to 6 wt% Cu, while they were detected at 15 wt% Cu. NH3 adsorption and the SCR reaction were followed in situ by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) on mesoporous ZrO2 and on one-pot synthesized 3 wt% Cu/ZrO2. Cu was found to improve the NH3 adsorption capacity of the catalyst by enhancing the Lewis functionality. The catalysts were efficient for SCR at low temperature, at 150 °C 75% of NO was converted over 6 wt% Cu/ZrO2 at water-free conditions. Increasing the copper loading while maintaining the dispersion improved NOx conversion.