Catalysing a sustainable future: Harnessing solar energy with novel Co3O4@VO2 nanocomposites for enhanced photocatalytic hydrogen generation and dye degradation

This study focuses on the hydrothermal synthesis and characterization of Concentration dependent Co3O4@VO2 nanocomposites with varying molar ratios of Co3O4 to VO2 (2:1, 1:1, and 1:2) for efficient hydrogen generation and dye degradation. The structural and morphological characteristics of the prepared nanocomposites were analysed using x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Crystallographic analysis using XRD confirmed the formation of crystalline Co3O4 with a monoclinic structure, while the presence of VO2 was identified by characteristic peaks in the XPS. Microscopic analysis using SEM and TEM revealed well-dispersed nanocomposites with nanoscale dimensions. Photocatalytic activities were evaluated for hydrogen evolution and dye degradation, with the nanocomposite featuring a 2:1 ratio of Co3O4 to VO2 (CV-21) demonstrating significantly enhanced performance. CV-21 exhibited a lower onset potential and higher current density for hydrogen evolution (2270μmol/h/g), indicating improved photocatalytic activity. Additionally, it displayed rapid and superior dye degradation (93% within 10 min) under sunlight compared to Victoria blue B (VBB) dye. The Co3O4@VO2 nanocomposites, particularly CV-21, demonstrate enhanced photocatalytic performance for hydrogen generation and dye degradation compared to pristine VO2 and Co3O4. This improvement possibly due to synergistic effects between Co3O4 and VO2, optimized structural characteristics, and improved interfacial properties in the nanocomposite structure. These findings highlight the promising potential of Co3O4@VO2 nanocomposites, particularly CV-21, for environmental remediation applications.