Local structure of copper centers obtained during solid-phase synthesis in copper–mordenite zeolite

The influence of temperature conditions for synthesis on the nearest-neighbor environment of copper atoms in copper–mordenite zeolites produced by solid-phase ion exchange has been investigated. The models of the local atomic structure of active copper centers in copper–mordenite zeolite at 300 and 400$^\circ$C have been established using two complementary techniques: X-ray absorption spectroscopy and density functional theory. It has been found that, at 300$^\circ$C, the copper atom does not have another one in its nearest-neighbor environment (monocentric model), whereas at 400$^\circ$C the center contains at least two copper atoms, which form Cu–O–Cu bridges. The structural parameters of Cu–O bonds have been determined.