Triazine- and porphyrin-based donor-acceptor microporous conjugated polymers for enhanced photocatalytic hydrogen production activity

Donor-acceptor type conjugated microporous polymers (D-A CMPs) have recently gained popularity as active components for photocatalytic hydrogen evolution from water due to their ability to separate the photoinduced holes and electrons efficiently and vastly absorb visible light. However, creating a novel CMP photocatalyst with high photoconversion efficiency is still difficult. Porphyrins and triazines exhibit intriguing electrical and optical features. We present here the directed synthesis and photocatalytic activity in hydrogen generation of two donor-acceptor isostructural triazine- and porphyrin-based conjugated microporous polymers (H-Por-TPT and Zn-Por-TPT CMPs). Our data demonstrate that both CMPs have extremely high specific surface areas (around 650 m2 g−1) and thermal stabilities (Td10: equal to 629 °C with char yields equal to 76 wt%). Introducing a Zn atom into a porphyrin ring profoundly influences its optoelectronic properties and photocatalytic efficiency for hydrogen generation from water. Zn-Por-TPT CMP has one of the highest reported values for a D-A CMP, with a photocatalytic hydrogen evolution rate of 11450 μmol g−1 h−1 when exposed to visible light. In addition, the Zn-Por-TPT CMP is notable not just for increasing the rate of hydrogen generation but also for improving photocatalysis stability during prolonged irradiation for roughly 30 h. These CMPs may prove useful as organic photocatalysts in future photocatalytic H2 production from water applications.