Probing the Cu Sites of Hierarchical SAPO-34

Inexpensive and durable catalysts for removal of greenhouse gasses and atmospheric pollutants, such as NOx-gasses, are highly sought after in power hungry industries. Cu2+ incorporated into a highly porous network such as SAPO-34 provides a cheap, high surface area catalyst which is stable at high temperatures. To enhance the gas diffusion and improve the catalyst lifetime, a hierarchical mesopore structure has therefore been developed. With the introduction of larger mesopores, the catalytic sites may not be solely confined to the micropores anymore. In-situ EXAFS measurements of the Cu K-edge using isobutane oxidation as a model reaction would reveal how the Cu environment changes during operation in the mesopores. The distribution of Cu in the micropores and mesopores at different Cu loadings can then be used to assess at which point the micropores become saturated with Cu.