High-Performance Visible-Light Photocatalysts for H₂ Production: Rod-Shaped Co₃O₄/CoO/Co₂P Heterojunction Derived from Co-MOF-74

Photocatalyst systems generally consist of catalysts and cocatalysts to realize light capture, charge carrier migration, and surface redox reactions. Developing a single photocatalyst that performs all functions while minimizing efficiency loss is extremely challenging. Herein, rod-shaped photocatalysts Co₃O₄/CoO/Co₂P are designed and prepared using Co-MOF-74 as a template, which displays an outstanding H₂ generation rate of 6.00 mmol·g⁻¹·h⁻¹ when exposed to visible light irradiation. It is 12.8 times higher than pure Co₃O₄. Under light excitation, the photoinduced electrons migrate from the catalysts of Co₃O₄ and CoO to the cocatalyst Co₂P. The trapped electrons can subsequently undergo a reduction reaction to produce H₂ on the surface. Density functional theory calculations and spectroscopic measurements reveal that enhanced performance results from the extended lifetime of photogenerated carriers and higher charge transfer efficiency. The ingenious structure and interface design presented in this study may guide the general synthesis of metal oxide/metal phosphide homometallic composites for photocatalysis.