Efforts to improve the overall efficiency of photoelectrochemical water splitting by promoting interfacial charge transfer and suppressing electron–hole recombination remain a challenge. Highly porous Co₃O₄@carbon derived from metal–organic frameworks was successfully embedded on the surface of BiVO₄ nanosheets. The Co₃O₄@carbon/BiVO₄ composites were fully characterised by a variety of techniques, including powder XRD, diffuse reflectance UV/Vis spectroscopy, BET surface area calculations, SEM, TEM, energy-dispersive X-ray spectroscopy, high-angle annular dark-field scanning TEM, and X-ray photoelectron spectroscopy. The construction of a heterojunction between porous Co₃O₄ (p-Co₃O₄) and BiVO₄ significantly promoted charge transfer and suppressed the recombination of holes and electrons. Consequently, the p-Co₃O₄@carbon/BiVO₄ photoanode demonstrated approximately tenfold higher photocurrent density relative to bare BiVO₄ and bulk Co₃O₄/BiVO₄ for water oxidation under the same conditions. Also, this system displayed good durability for water oxidation and could be recycled at least three times without any loss of catalytic activity.

ChemPlusChem,2015