Hydrogen sulfide is efficiently oxidized to sulfate in aqueous solutio
n in the presence of water soluble Zn and Al phthalocyanines 2-4 as ph
otocatalysts by irradiation with visible light (model reaction for sol
ar radiation). Co phthalocyanine 1 exhibits similar activity in the da
rk and under irradiation with formation of thiosulfate as oxidation pr
oduct. Singlet dioxygen is involved in the photooxidation process.