Covalent\nTriazine Frameworks Embedded with Ir Complexes\nfor Enhanced Photocatalytic Hydrogen Evolution

Abstract

Covalent triazine\nframeworks (CTFs) with two-dimensional conjugated\nstructures and a high nitrogen content have potential for photocatalytic\nhydrogen evolution (PHE). Herein, we show a strategy to boost the\nphotocatalytic performance of a CTF containing bipyridine (bpy) units\n(PhBp-CTF). Through a postcomplexation reaction of the PhBp-CTF with\nIr₂(ppy)₄(μ-Cl)₂, the Ir complexes\nof [Ir­(bpy)­(ppy)₂]³⁺ are successfully embedded\ninside to form PhBp-CTF-Ir. The accurate content and valence state\nof Ir have been confirmed by advanced spectroscopies. PhBp-CTF-Ir\nshows a PHE rate of 4805 μmol g^–1 h^–1, while its precursor without Ir complexes has a rate of 3175 μmol\ng^–1 h^–1. The enhanced photocatalytic\nperformance is attributed to the Ir complexes inside PhBp-CTF-Ir,\nwhich act as not only an effective photosensitizer but also a proton\nreduction catalyst.