Self-assembled naphthalimide-substituted porphyrin nanowires for photocatalytic hydrogen evolution

Abstract

A linear 5,15-di(naphthalimide) substituted porphyrin ZnD(p-NI)PP is facilely self-assembled into nanowires in solid with well-defined morphology through the synergistic π-π stack interactions of both porphyrin and naphthalimide skeletons. The self-assembled porphyrin nanowires feature broadened light absorption, efficient separation and transfer of photogenerated charges, and enhanced photostability. As a consequence, the ZnD(p-NI)PP produced 108 times higher H2 production rate (ηH2 = 5.40 mmol g-1 h-1) than the control 5,15-diphenylporphyrin (ZnDPP) (ηH2 = 0.05 mmol g-1 h-1) and 3.6-fold higher than the ZnT(p-NI)PP (ηH2 = 1.50 mmol g-1h-1) which bears four NI units and self-assembled into nanospheres in the solid. Additionally, the photocatalytic system of ZnD(p-NI)PP produced hydrogen evolution up to 50 h, while the hydrogen evolution of the ZnDPP photocatalytic system reached a plateau after 20 h.