Covalent Triazine Frameworks Embedded with Ir Complexes for Enhanced Photocatalytic Hydrogen Evolution
Nanfeng Xu, Yingxue Diao, Zhengtao Xu, Hanzhong Ke, Xunjin Zhu
Abstract
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 Ir<sub>2</sub>(ppy)<sub>4</sub>(<i>μ</i>-Cl)<sub>2</sub>, the Ir complexes of [Ir(bpy)(ppy)<sub>2</sub>]<sup>3+</sup> 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 <i>μ</i>mol g<sup>-1</sup> h<sup>-1</sup>, while its precursor without Ir complexes has a rate of 3175 <i>μ</i>mol g<sup>-1</sup> h<sup>-1</sup>. 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.