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 semi-conducting feature and broad spectral response ability. The Zn-CoDETPP polymer exhibits a photocatalytic H-2 generation activity (43 mu mol h(-1)) illuminated by lambda >= 400 nm light and a record apparent quantum yield (7.36%) at lambda = 400 nm monochromatic light among those porphyrin-based polymers reported previously, while the Zn-ZnDETPP and Co-CoDETPP only deliver a H-2 generation activity of 8.0 and 33 mu mol 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 H-2 generation reaction. The present results open up a promising strategy applying porphyrin-based conjugated polymers as intrinsic semiconductors for efficient H-2 generation and instruct us to efficiently convert solar energy into chemical energy by molecular designing.