Interfacing Broad-Spectrum Semiconductors with Hydrogenases for Semi-Artificial Solar Reforming of Cellulose

Semiartificial photosynthesis offers a promising route for solar chemistry, but most biohybrid systems rely on UV or blue-light excitation, are limited by inefficient interfacial charge transfer, or rely on sacrificial reagents. Here, we report a rationally designed hybrid system that integrates the broad-spectrum semiconductor BaTaO₂N (up to ∼680 nm) with carbon nitride (CN_x) and the [FeFe]-hydrogenase (H₂ase) from Clostridium pasteurianum for solar-driven biomass reforming. In this architecture, BaTaO₂N serves as a robust broad-spectrum light absorber to complement the narrow UV-blue wavelength absorption of CN_x, which functions as both a photoactive component and an interfacial conduit to shuttle photogenerated electrons to [FeFe]-H₂ase for H₂ evolution. The optical advantage of the BaTaO₂N|CN_x|[FeFe]-H₂ase hybrid enables markedly enhanced catalytic efficiency, achieving a H₂ yield of 413 ± 21 μmol g^-1 and a turnover number of 20,653 for cellulose reforming under simulated AM 1.5G irradiation at 25 °C. This work establishes an advanced design strategy for semiartificial photoreforming by combining broadband light harvesting, efficient charge transfer, and sustainable biomass valorization.