Photocatalysts for H 2 Generation from Starburst Triphenylamine/Carbazole Donor‐Based Metal‐Free Dyes and Porous Anatase TiO 2 Cube

A series of novel triphenylamine/carbazole‐based D–D–π–π–A dyes DH1–4 and a mesoporous anatase cubic “microcage” TiO 2 material (denoted as MC‐TiO 2 ) were synthesized and combined to obtain dye‐sensitized photocatalysts (denoted as DH n /Pt/MC‐TiO 2 , n =1–4). These catalysts showed better performances in visible‐light‐driven H 2 evolution from water than DH n /Pt/P25‐TiO 2 catalysts based on commercial P25‐TiO 2 bulk semiconductor under similar conditions. Compared with P25‐TiO 2 particles, the porous MC‐TiO 2 had a large Brunauer–Emmett–Teller surface area, porosity, and exposed {0 0 1} crystal plane, which greatly contributed to the photocatalytic activity. The optimized DH2/Pt/MC‐TiO 2 photocatalyst exhibited an attractive H 2 production rate (16.28 mmol g −1  h −1 based on catalyst mass), and the optimized DH4/Pt/MC‐TiO 2 photocatalyst showed good stability [turnover number (TON) of 16 699 in 105 h based on dye number], which represents one of the best performances among all reported visible‐light‐driven heterogeneous catalytic systems. Compared with the other dyes in this series, the high H 2 production rate of DH2 on Pt/MC‐TiO 2 can be attributed to its size‐matching effect and thus high dye loading amount, whereas the high TON and durability of DH4/Pt/MC‐TiO 2 are probably related to the rapid regeneration kinetics of DH4.