photocatalyst

Etymology tree
Proto-Indo-European *bʰeh₂-
Proto-Indo-European *bʰéh₂os
Proto-Hellenic *pʰáwos
Ancient Greek φᾰ́ος (phắos)
Ancient Greek φῶς (phôs)
Ancient Greek φωτο- (phōto-)der.
English photo-
English catalysis
Proto-Indo-European *-id-
Proto-Indo-European *-yéti
Proto-Indo-European *-idyéti
Proto-Hellenic *-íďďō
Ancient Greek -ῐ́ζω (-ĭ́zō)
Proto-Hellenic *-tās
Ancient Greek -τής (-tḗs)
Ancient Greek -ῐστής (-ĭstḗs)bor.
Latin -istader.
Old French -istebor.
Middle English -ist
English -ist
English catalyst
English photocatalyst
From photo- + catalyst.