Ag/Mg-Al-O Composite for Low Temperature NOx Storage

Ag/Mg-Al-O composite was prepared by the calcination of Ag-containing Mg-Al hydrotalcite-like compound and metallic Ag supported on periclase phase Mg-Al-O was obtained. The as-prepared Ag/Mg-Al-O composite exhibits good NO, storage capability in a relatively low temperature range of 150-300 degrees C. The highest NO, storage capability of 7.3 mg/g was achieved at 150 degrees C, while a lower NO, storage capability of 5.1 mg/g was achieved at 300 degrees C. Meanwhile, ca. 25% of NO, was observed to decompose to N-2 at 300 degrees C. In situ FTIR results suggest that NO, mainly stored in Ag/Mg-Al-O catalyst in the form of bridging nitrites located on periclase phase Mg-Al-O.