Donor-acceptor porphyrin functionalized Pt nano-assemblies for artificial photosynthesis: a simple and efficient homogeneous photocatalytic hydrogen production system

In this paper, a novel porphyrin dye (5,10,15,20-tetrakis (4-(anthracene-1-ylmethoxy)phenyl) porphyrin, TPPAN) and its functionalized platinum nanoparticles (Pt-TPPAN) were synthesized. Using the Pt-TPPAN nanocomposite as a photocatalyst, a new and more compact photoinduced hydrogen evolution system from an aqueous ethanol solution without additives was developed. Fluorescence and photo-electrochemical spectra reveal that photoinduced electron transfer occurs from the photoexcited state of anthracene substituents to the porphyrin, accompanied by an electron transfer from the excited porphyrin moiety to the Pt co-catalyst. The photocatalytic activity results suggested that this TPPAN functionalized Pt nano-assembly could efficiently catalyze hydrogen evolution from an aqueous ethanol solution under simulated solar light irradiation. Therein, the TPPAN molecule in the nanocomposite worked as a light absorption antenna and the nanocore Pt species acted as a co-catalyst. This investigation might offer a new paradigm for constructing a simpler and more efficient homogeneous photocatalytic hydrogen evolution system for mimicking natural photosynthesis.