Consecutive Charging of a Perylene Bisimide Dye by Multistep Low‐Energy Solar‐Light‐Induced Electron Transfer Towards H₂ Evolution

Abstract

A photocatalytic system containing a perylene bisimide (PBI) dye as a photosensitizer anchored to titanium dioxide (TiO2) nanoparticles through carboxyl groups was constructed. Under solar‐light irradiation in the presence of sacrificial triethanolamine (TEOA) in neutral and basic conditions (pH 8.5), a reaction cascade is initiated in which the PBI molecule first absorbs green light, giving the formation of a stable radical anion (PBI.−), which in a second step absorbs near‐infrared light, forming a stable PBI dianion (PBI2−). Finally, the dianion absorbs red light and injects an electron into the TiO2 nanoparticle that is coated with platinum co‐catalyst for hydrogen evolution. The hydrogen evolution rates (HERs) are as high as 1216 and 1022 μmol h−1 g−1 with simulated sunlight irradiation in neutral and basic conditions, respectively.

Efficient Mineralization of Organic Pollutants Using Visible-light-induced PTCDA Anions Electronic Reservoir and Photogenerated Holes

“…The PTCDA anions exhibited a different color from their own that enabled them to be tested by ultraviolet-visible (UV-Vis) light irradiation 38,39 . New absorption bands of PTCDA anion appeared at ~ 668, ~755 and ~ 788 nm under irradiation of λ 350 nm, and the maximum amount of PTCDA anions was obtained when irradiated with simulated sunlight (Fig.…”

Organophotocatalytic Mechanisms: Simplicity or Naïvety? Diverting Reactive Pathways by Modifications of Catalyst Structure, Redox States and Substrate Preassemblies

“…Elsewhere, inspired by the work of König and co‐workers, Würthner, Xie and co‐workers have demonstrated how carboxyphenyl‐substituted PDI s ( cp‐PDI s) can be charged consecutively with triethanolamine (TEOA) in a conPET‐type manner to cp‐PDI 2 − which when loaded onto Pt‐doped TiO 2 culminates in a highly photoactive hydrogen evolution reaction material [83f] . In their study (not shown), π‐stacking aggregation of neutral cp‐PDI was observed, and it was proposed that the further reductive PET from TEOA to cp‐PDI ⋅ − must occur by a preassembly given the ultrashort lifetime of * cp‐PDI ⋅ − (145 ps, measured by transient absorption spectroscopy) prohibiting diffusion‐controlled reductive quenching.…”

Recent Progress and Challenges in Perylene Small Molecules, Assemblies and Composites for Photocatalytic Hydrogen Evolution

“…Xie, Würthner and co-workers presented a consecutive charging mechanism within a single photocatalytic system for the first time for H 2 evolution that enables absorption in a wide range and covers the entire visible region of solar spectrum. [56] Perylene diimide substituted with four carboxyphenoxy groups (cp-PDI) 6 at bay position (Figure 3c) was synthesized to anchor onto TiO 2 nanoparticles loaded with Platinum. The H 2 evolution experiments were carried out in the presence of TEOA at neutral and basic (8.5) pH conditions.…”