Biomorphic CdS/Cd Photocatalyst Derived from Butterfly Wing for Efficient Hydrogen Evolution Reaction

Abstract Photocatalytic splitting of water into hydrogen has attracted growing concerns as a promising strategy for the development of clean and renewable energy sources. Fabricating novel photocatalysts with high H₂ evolution rate and good cyclic stability is extremely vital for practical applications. Herein, a novel CdS/Cd₂SO₄(OH)₂ composite derived from cadmium nitrate doped Cd‐MOF is deposited on the surface of butterfly wings with reticular hierarchical structure for efficient hydrogen evolution reaction. The combination of unique hierarchical structure and MOF‐derived CdS nanoparticles endows them with strong light absorbability, small band gap, and superior photogenerated charges separation efficiency, leading to excellent photocatalytic efficiency. Furthermore, in‐depth measurements reveal the reduction of Cd₂SO₄(OH)₂ to Cd on the surface of CdS particle during the photocatalytic process. The obtained Cd metal can act as the electron trap to improve the charge separation efficiency and further promote the hydrogen production performance. As a result, the MOF‐derived CdS/Cd₂SO₄(OH)₂ and final CdS/Cd systems with reticular hierarchical structure exhibit significantly enhanced hydrogen production performance compared with CdS/Cd₂SO₄(OH)₂ powder and MOF‐derived CdS nanoparticles under visible light irradiation. It is expected that this synthetic approach can be used to fabricate other composite photocatalyst materials with reticular hierarchical structure for efficient water splitting to hydrogen.