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Updated: Jun 16, 2026

Developing Photosensitizer-Cobaloxime Hybrids for Solar-Driven H2 Production in Aqueous Aerobic Conditions
Published on: October 5, 2019
High-Efficiency and Stability Phenothiazine-Based D-(A'-π-A)2 Sensitized Photocatalytic Hydrogen Evolution Under
Yu Hsuan Lin1, Xiao-Feng Shen2,3, Yu-Tong Hung1
1Department of Chemistry, Tunghai University, Taichung, Taiwan.
None:
Three novel phenothiazine (PTZ)-based photocatalysts were rationally designed and integrated with Pt@TiO2 for photocatalytic hydrogen evolution. PTZ-1 adopts a D-(π-A)2 architecture, whereas PTZ-2 and PTZ-3 feature D-(A'-π-A)2 configurations incorporating benzothiadiazole (BTD) and isoindigo as auxiliary acceptors, respectively. All photocatalysts were immobilized on Pt@TiO2 through dianchoring groups to ensure efficient interfacial charge transfer. In particular, PTZ-2-incorporating benzothiadiazole as an auxiliary electron acceptor-exhibited the highest photocatalytic activity, delivering a high turnover number (TON) and turnover frequency (TOF) of 10,714.2 and 691.2 (after 15.5 h), respectively, with total hydrogen evolution of 92,534 μmol g-1 after 15.5 h and 264,646 μmol g-1 after 60 h at a dye loading of 17.9 μmol g-1. This superior performance is primarily attributed to favorable energy-level alignment and enhanced electron-injection efficiency imparted by the BTD unit. Notably, PTZ-2 displays the longest electron lifetime (0.62 ns) and the lowest charge-transfer resistance, indicating efficient charge separation and suppressed recombination. Furthermore, PTZ-2 retained 97% of its initial hydrogen-evolution activity after 60 h under identical conditions, demonstrating excellent long-term stability under visible light.
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