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 Co 3 O 4 /CoO/Co 2 P are designed and prepared using Co-MOF-74 as a template, which displays an outstanding H 2 generation rate of 6.00 mmol·g −1 ·h −1 when exposed to visible light irradiation. It is 12.8 times higher than pure Co 3 O 4 . Under light excitation, the photoinduced electrons migrate from the catalysts of Co 3 O 4 and CoO to the cocatalyst Co 2 P. The trapped electrons can subsequently undergo a reduction reaction to produce H 2 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.