FORMATION AND INTERACTION OF CARBONYLS AND NITROSYLS ON GOLD(I) IN ZSM-5 ZEOLITE CATALYTICALLY ACTIVE IN NO REDUCTION WITH CO

A combined XRD and XPS study showed that the Au(I)/ZSM-5 zeolite (Au 4f7/2,5/2 = 85.6 and 89.2 eV) can be prepared by spontaneous monolayer dispersion of AuCl3 in ZSM-5 followed by reductive carbonylation with CO at 343 K. The in-situ FTIR shows that the intrazeolite Au(I) in ZSM-5 provides Au(I) carbonyl (nu(CO) = 2170 cm-1) and nitrosyl (nu(NO) = 1817 cm-1) on chemisorption of CO (5-350 Torr) and NO (5-50 Torr) at 300 K, respectively. The interaction of CO and NO on Au(I)/ZSM-5 results in surface intermediates such as Au(I)(NO)2 (nu(NO) = 1837 and 1741 cm-1) and Au(I)NO52 (1620 and 1302 cm-1), which are catalytically active in NO reduction with CO producing N2O and CO2 at 293-373 K.