Z-Scheme LaCoO₃/g-C₃N₄ for Efficient Full-Spectrum Light-Simulated Solar Photocatalytic Hydrogen Generation

Photocatalytic decomposition of water is the most attractive method for the sustainable production of hydrogen, but the development of a highly active and low-cost catalyst remains a major challenge. Here, we report the preparation of LaCoO₃/g-C₃N₄ nanosheets and the utilization of LaCoO₃ instead of noble metals to improve the photocatalytic activity for the production of hydrogen. First, LaCoO₃ was successfully prepared by the sol-gel method, and then a series of highly efficient Z-scheme LaCoO₃/g-C₃N₄ heterojunction photocatalysts were synthesized by the solvothermal method. Various characterization techniques (X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy (DRS), photoluminescence (PL), transient photocurrent response test, electron paramagnetic resonance (EPR)) confirm that the heterostructure and interfacial interaction had been formed between LaCoO₃ nanoparticles and g-C₃N₄ nanosheets. In the photocatalytic water splitting test, LaCoO₃/g-C₃N₄-20 wt % exhibited the highest photocatalytic activity of 1046.15 μmol h^-1 g^-1, which is 3.5 and 1.4 times higher than those of LaCoO₃ and g-C₃N₄, respectively. This work leads to an inexpensive and efficient LaCoO₃/g-C₃N₄ photocatalysis system for water splitting or other photocatalytic applications.