Double‐Anchored Triphenylamine‐Fluorene Functionalized Dyes for High‐Performance Photocatalytic Hydrogen Generation

Abstract Two novel metal‐free organic dyes, namely the mono‐anchoring KMT1 and di‐anchoring KMT2 dyes, have been synthesized to function as photosensitizers for utilizing in photocatalytic hydrogen production systems. They adopt the donor‐donor‐π‐acceptor and donor‐donor‐(−π‐acceptor) 2 configurations, respectively, featuring triphenylamine and fluorene moieties as electron donors, thiophene as the π‐bridges and cyanoacrylic acid as the acceptors/anchoring groups. It was found that the photocatalytic performance of the di‐anchoring dye significantly outperforms that of its mono‐anchoring counterpart. KMT2 ‐based photocatalytic system demonstrated remarkable performance, producing 3520 μmol (84.9 mL) of hydrogen over a span of 257 hours under blue light irradiation, with a turnover number (TON) of 56300, a turnover frequency (TOF i ) of 1862.7 h −1 , an initial hydrogen production activity (activity i ) of 1164180 and an apparent quantum yield (AQY i %) of 19.9. This performance is among the top‐tier when compared to other dyes used in similar photocatalytic systems. The results clearly illustrate that the di‐anchoring dye possesses several advantages, including a broad absorption spectrum, higher absorptivity, and a relatively slower charge recombination rate. These attributes collectively contribute to its superior overall performance in photocatalysis.