Using block copolymers to enhance photosensitized water reduction for hydrogen gas generation

Abstract

We demonstrate a new approach of using block copolymers to enhance the photosensitized reduction of water to hydrogen (H₂). We investigated a complex formed by a diblock copolymer comprising poly(acrylic acid) and poly(4-vinyl pyridine) (PAA₄₅-b-P4VP₉₀) with Zn(II) protoporphyrin IX (ZnPP) using rhodium trisbipyridine chloride (Rh(bpy)₃Cl₃) as the electron acceptor and triethanolamine (TEOA) as the sacrificial electron donor. We show that ZnPP is bound to the copolymer by an axial coordination with the P4VP block, which improves its solubility in water and leads to a much more enhanced generation of hydrogen gas as compared to the neat photosensitizer without the block copolymer under the same conditions.