Supercell model of widely used zeolite ZSM-5
Two silicon atoms are substituted with aluminum. Two Broensted acid sites are the result from such substitution. In this model, one Broensted acid site is deprotonated while the second site remains protonated. The 6-membered rings are hypothesized to be the locations of very strong acid sites. This was confired in our most recent research. The large acidity can have a detrimental effect on catalytic reactions by reducing selectivity and causing catalyst deactivation.
