Catalyst able to produce, upon absorption of light, chemical transformations of the
reaction partners. The
excited state of the photocatalyst repeatedly interacts
with the reaction partners forming reaction intermediates and regenerates itself
after each cycle of such interactions.
Source:
PAC, 2007, 79, 293
(Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006))
on page 384