Zr/CuOx catalysts derived from MOFs for the selective catalytic reduction of NOx with NH3

MOF derivative (Zr (0.9)/CuO x (400)) had excellent denitrification activity, N 2 selectivity and stability. • Systematically revealed the regulation mechanism of Zr doping on the Cu 2+ /Cu + ratio and acid balance. • Proved that Zr doping could act as sacrificial sites to greatly improve the H 2 O and SO 2 resistance of the catalyst. Zr/CuO x composite were synthesized by hot-solvent and calcination method using metal-organic framework (MOF) as the precursor, and were applied for selective catalytic reduction of NO x with NH 3 (NH 3 -SCR). The effects of Zr/Cu molar ratio, calcination temperature and time on catalyst activity and the physicochemical properties of the composites were systematically investigated. The results showed that Zr/CuO x composite revealed a favorable denitrification activity, stability and resistance to sulfur and water while Zr/Cu molar ratio was 0.9 and calcination temperature was 400 °C. When the NO concentration of 500 ppm and gas hourly space velocity (GHSV) of 35,000 h -1 , NO conversion efficiency was achieved 100% and over 94% N 2 selectivity at 275–375 °C. In the presence of 100 ppm SO 2 and 10 vol% H 2 O, the NO conversion of Zr (0.9)/CuO x (400) approached 92%. The enhanced activity was attributed to a synergistic Zr/Cu interaction that optimized the surface Cu 2+ /Cu + redox couple, enriched Cu + sites, and thereby accelerated the low-temperature “fast” SCR pathway. Moreover, doping Zr generated a larger number of well-dispersed acid sites and maintained strong reducibility across a broad temperature range, collectively providing favorable conditions for the NH 3 -SCR. Download: Download high-res image (230KB) Download: Download full-size image