⁶⁵Cu NMR Spectroscopy of Cu-Exchanged ZSM-5 Catalysts

65Cu NMR and 65Cu−27Al spin-echo, double-resonance (SEDOR) measurements from Cu-exchanged ZSM-5 catalysts are reported. The presence of Cu+ cations in CuZSM-5 was detected directly by 65Cu NMR; upon heating, we observed the autoreduction of Cu2+ to Cu+. It was found that the Cu+ cations can be reduced further to Cu0 by exposure to carbon monoxide at high temperatures. The internuclear distance between the two quadrupolar nuclei Cu (spin-3/2) and Al (spin-5/2) was determined to be 0.23 ± 0.02 nm, in good agreement with the value of 0.24 nm obtained from density functional theory calculations.