Porphyrin-Based Conjugated Polymers as Intrinsic Semiconducting Photocatalysts for Robust H₂ Generation under Visible Light

Up to now, conjugated organic polymers as organic semiconductors have received more and more attention on the direct conversion of water to hydrogen energy. Herein, we designed and synthesized a series of porphyrin-based conjugated polymers (Zn-ZnDETPP, Co-CoDETPP, and Zn-CoDETPP) with intrinsic semiconducting feature and broad spectral response ability. The Zn-CoDETPP polymer exhibits a photocatalytic H2 generation activity (43 μmol h–1) illuminated by λ ≥ 400 nm light and a record apparent quantum yield (7.36%) at λ = 400 nm monochromatic light among those porphyrin-based polymers reported previously, while the Zn-ZnDETPP and Co-CoDETPP only deliver a H2 generation activity of 8.0 and 33 μmol h–1 respectively. The characteristic results demonstrate that the CoDETPP porphyrin units as bridges in the Zn-CoDETPP polymer can act as an electron acceptor and promote the metal-to-metal charge transfer (MMCT) from zinc porphyrin to cobalt porphyrin units, which could lead to more effective and faster charge separation in the Zn-CoDETPP polymer for the H2 generation reaction. The present results open up a promising strategy applying porphyrin-based conjugated polymers as intrinsic semiconductors for efficient H2 generation and instruct us to efficiently convert solar energy into chemical energy by molecular designing.