Donor–acceptor conjugated microporous polymers based on Thiazolo[5,4-d]thiazole building block for high-performance visible-light-induced H2 production

Abstract

Recently, significant advancement has been achieved in the rational design of donor-acceptor type conjugated microporous polymers (D-A CMPs) photocatalysts that enable effective separation of photoinduced holes and electrons and absorb visible light extensively for hydrogen production. However, developing a new CMP photocatalyst with high photoconversion efficiency remains a challenge. Herein, we constructed and synthesized for the first time a new tetrabromo-functionalized acceptor 2,5-bis(3,5-dibromophenyl)thiazolo[5,4-d]thiazole (TzTz-4Br), which was further applied to construct several novels semiconducting D–A type CMP photocatalysts by Suzuki-copolymerizing with various donor units for the photocatalytic activity of hydrogen production from water. Here, we used pyrene (Py), N1,N1,N4,N4-tetraphenylbenzene-1,4-diamine (TPA), and 9,9′-bicarbazole (BC) as the donors. The obtained D–A CMPs exhibit massive thermal stabilities (Td10: equal to 534 °C with char yields equal to 75 wt %) and specific surface areas (equal to 988 m2 g−1). Interestingly, in the exclusion of Pt-co-photocatalyst, the TzTz-Py D–A CMP and ascorbic acid (sacrificial electron donor) provide high photocatalytic performance and a hydrogen evolution rate (HER), reaching 3.71 mmol g−1 h−1 (λ = 380–780 nm). The obtained HER value is one of the largest reported values for a D–A CMP to date. These CMPs appear to have the potential to be beneficial as organic photocatalysts for the prospective photocatalytic H2 generation from water.