Journal of Physical Chemistry, Vol.99, No.2, 479-482, 1995
Improvement of Raman-Spectra of SAPO-5 by Chromium(III)-Induced Luminescence Quenching
Addition of small amounts of Cr(NO3)(3) X 9 H2O during the hydrothermal synthesis of SAPO-5 produced pseudooctahedrally coordinated chromium(III) species within the unidimemsional channel system of the molecular sieve. A broad intense photoluminescence that occurs in the visible region upon 532 nm photoexcitation of calcined SAPO-5 is efficiently quenched in Cr-SAPO-5 allowing for unobstructed detection of Raman scattering spectra. The photoluminescence quenching mechanism appears to involve an energy transfer; from the molecular sieve photoexcited surface states to the metastable chromium(III) (2)E state, giving rise to the well-known chromium(III) 2(E) --> (4)A(2) luminescence at 696 nn.
Keywords:FAUJASITIC ZEOLITES;SPECTROSCOPY