Enhancement of NO-elimination activity of Co-silicate catalyst by high-temperature calcination in steam-containing air

H–Co-silicate having an MFI structure (CoMFI), calcined in steam-containing air at 800°C (CoMFI-800S), was characterized by XRD and diffuse reflectance electron absorption (EA). The calcination educed some of the Co ions from the CoMFI framework to make small clusters nearby. The CoMFI-800S performance in NO elimination in the presence of excess O2 was compared with that of Co supported on siliceous MFI zeolite ([Co]SiMFI), Co supported on H–Co-silicate ([Co]CoMFI), and a physical mixture of CoMFI and [Co]SiMFI (Co+[Co]). The educed Co ions enhanced NO elimination due to the uniform and isolated dispersion of oxidized Co clusters.