Covalent Triazine Frameworks Embedded with Ir Complexes for Enhanced Photocatalytic Hydrogen Evolution

Covalent triazine frameworks (CTFs) with two-dimensional conjugated structures and a high nitrogen content have potential for photocatalytic hydrogen evolution (PHE). Herein, we show a strategy to boost the photocatalytic performance of a CTF containing bipyridine (bpy) units (PhBp-CTF). Through a postcomplexation reaction of the PhBp-CTF with Ir₂(ppy)₄(μ-Cl)₂, the Ir complexes of [Ir(bpy)(ppy)₂]³⁺ are successfully embedded inside to form PhBp-CTF-Ir. The accurate content and valence state of Ir have been confirmed by advanced spectroscopies. PhBp-CTF-Ir shows a PHE rate of 4805 μmol g^-1 h^-1, while its precursor without Ir complexes has a rate of 3175 μmol g^-1 h^-1. The enhanced photocatalytic performance is attributed to the Ir complexes inside PhBp-CTF-Ir, which act as not only an effective photosensitizer but also a proton reduction catalyst.