2D Conjugated Polymers Containing B←N Units for Improved Photocatalytic Hydrogen Evolution

Abstract

Previous studies have demonstrated linear polymers embedded with B←N units display efficient photocatalytic hydrogen evolution performance, but their limited structural tunability restricts photogenerated carrier dynamics modulation. Current researches mainly focus on linear polymers, while the study of B←N units in the field of two-dimension conjugated polymers (2DCPs) photocatalytic hydrogen evolution remains an uncultivated ground. Herein, three 2DCPs containing B←N units were synthesized and their photocatalytic hydrogen production performance was investigated. Among them, the BN-Tz exhibited the best property with a hydrogen production rate of 89.5 μmol·h ^–1, while BN-Ph and BN-TPB were only 26.4 and 8.5 μmol·h ^–1, respectively. Comprehensive analyses showed that the remarkable photocatalytic ability of BN-Tz catalyst was mainly attributed to its superior transport and separation of photogenerated carriers, as well as the ability to construct a stronger built-in electric field and better planarity. Meanwhile, it was found that the manipulation of the electronic properties of the structures connected to the B←N unit could effectively regulate the molecular polarity, thus achieving the control of the electronic structure of the materials. This work extends the application of materials containing B←N units in photocatalysis and lays a good foundation for the subsequent design of photocatalysts containing B←N units.

Keywords

Boron / B←N unit / Two-dimensional conjugated polymers / Photocatalysis / Hydrogen / Built-in electric field / Planarity / Molecular polarity

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2024 SIOC, CAS, Shanghai, & WILEY-VCH GmbH.