Enhanced sunlight-driven catalysis for hydrogen generation and dye remediation using synergistic p-Co3O4/n-TiO2 nanocomposites

Abstract

In this study, p-Co₃O₄/n-TiO₂ nanocomposites were synthesized using different ratios of cobalt and titanium precursors through a hydrothermal method. These nanocomposites demonstrated notable potential in photocatalytic applications for hydrogen production and orange-red dye degradation under sunlight. Various techniques, including XRD, Raman spectroscopy, XPS, FESEM, TEM, and BET analysis, were used to comprehensively characterize their structural, morphological, and optical properties. The nanocomposites exhibited both cubic and tetragonal phases of Co₃O₄ and TiO₂, and their combined effect resulted in a narrowed band gap. Additionally, the presence of Co₃O₄ induced surface plasmon resonance on the TiO₂ surface, effectively impeding electron–hole recombination. The nanocomposites displayed an average particle size of ∼20 to 30 nm with substantial visible light absorption. High crystallinity and well-dispersed nanocomposites were confirmed by XRD and Raman, with BET surface areas ranging between 49 and 106 m² g⁻¹. Notably, the p-Co₃O₄/n-TiO₂ nanocomposite showed superior photocatalytic activity, achieving a maximum hydrogen generation rate of 1120 μmol h⁻¹ g⁻¹ and an 83% degradation efficiency of the orange-red dye within 6 minutes under sunlight. This study emphasizes the enhanced performance of the p-Co₃O₄/n-TiO₂ nanocomposite, indicating its potential in photocatalytic applications, conforming to a pseudo-first-order kinetics model.