Tb(3+)and Eu(3+)ions were encapsulated for the first time in the inorganic layers
of a synthetic saponite clay following a one-pot synthetic approach. The co-presence
of the two metal ions led to tuneable light-emitting properties, promoted by an efficient
Tb3+-> Eu(3+)energy transfer and enhanced Stokes shift character. To our knowledge,
the so-prepared luminescent material was tested for the first time as an optical sensor
for the detection of chromate anions in water.