Photocatalytic hydrogen evolution without an electron mediator using a porphyrin-pyrene conjugate functionalized Pt nanocomposite as a photocatalyst

摘要

A new system for photoinduced hydrogen production has been constructed using a porphyrin-pyrene conjugate functionalized Pt nanocomposite as a photocatalyst and ethyl-enediaminetetraacetic acid (EDTA) as a sacrificial reductant in the absence of an electron mediator. Detailed spectral, computational and photochemical studies reveal that a photo-induced energy transfer from the photoexcited state of pyrene to the porphyrin occurs, accompanied by an electron transfer from the excited porphyrin moiety to the platinum catalyst for the H_2 generation. Efficient photocatalytic hydrogen evolution from the system demonstrates the possibility of constructing a photocatalytic system that uses a Pt nanocomposite functionalized by self-assembled donor-acceptor conjugates as a photocatalyst. The turnover numbers (TON_(Pt) and TON_(dye)) and quantum yields of hydrogen (Φ_(h_2)) for the photoinduced hydrogen production system are 63, 6311, and 2.65%, respectively, and are calculated on the basis that the total amount of H_2 evolved after 12 h of irradiation.