Construction of Efficient Photocatalytic Hydrogen Evolution System using Red Blood Cell Ghosts as Scaffold

The development of efficient photocatalytic hydrogen (H₂) evolution systems is attracting considerable interest owing to the usefulness of H₂ as a renewable and clean energy source. Widely studied systems for light-driven H₂ evolution consist of multiple components, and assembling these components on a scaffold is essential to facilitate electron transfer between them, to enable high H₂ yields. Here, red blood cell ghost (RBCG) is used as a scaffold to construct a three-component system comprising [Ru(bpy)₃]²⁺ (photosensitizer), methyl viologen (MV²⁺, electron relay), ethylnediaminetetraacetic acid (EDTA, sacrificial electron donor), and platinum nanoparticles (Pt NPs, catalyst). Pt NP-deposited RBCG (Pt@RBCG) and Pt NP- and Ru complex-deposited RBCG (Pt•Ru@RBCG) are prepared. In particular, the Pt@RBCG system comprising Pt@RBCG, [Ru(bpy)₃]²⁺, MV²⁺, and EDTA exhibits a higher H₂ yield than the system without RBCG. The Pt NPs, which are highly dispersed on the RBCG cytoskeleton, contribute to the high catalytic activity of Pt@RBCG for H₂ evolution. Furthermore, Stern-Volmer analysis and quantification of the methyl-viologen radical cation (MV^+•) reveal that the RBCG environment does not affect the electron transfer process or MV^+• formation in the Pt@RBCG system. This study demonstrates the versatility of RBCGs as a scaffold for controlling sophisticated reactions involving multiple components.