[FeFe]-Hydrogenase Encapsulated in Zeolitic Imidazolate Framework (ZIF)-8 Nanoparticles as a Robust Biocatalyst for Photocatalytic Hydrogen Production

[FeFe]-hydrogenase (HydA) is an active biocatalytic enzyme for solar-to-hydrogen (H₂) conversion. However, stability is a main challenge that limits practical applications. This work aims to encourage the efficiency of HydA by encapsulating it in the zeolitic imidazolate framework-8 (ZIF-8) as a synthetic protective shield. The construction of HydA@ZIF-8 nanoparticles, with an average diameter of 700-1000 nm, at ambient conditions can preserve HydA activity within a spatially confined microenvironment, as characterized by scanning electron microscopy and X-ray diffraction analysis. Based on MV^•+-dependent H₂ production activity and kinetic analysis, both the stability and efficiency of HydA@ZIF-8 surpass those of free HydA and whole-cell biocatalysts over a wider range of pH and temperature. The achievement of robust HydA@ZIF-8 construction represents a significant step forward in the development of biocatalysts for various future applications.