photocatalysis

noun

pho·​to·​ca·​tal·​y·​sis ˌfōt-ō-kə-ˈtal-ə-səs 

plural photocatalyses -ˌsēz 

: the acceleration of a chemical reaction by radiant energy (as light) acting either directly or by exciting a substance that in turn catalyzes the main reaction compare photoinactivation sense 1