Heterogeneous Fenton-like CuO-CoO_x/SBA-15 catalyst for organic pollutant degradation: synthesis, performance, and...

In this study, CuO-CoO_x/SBA-15 catalysts were successfully synthesized via ultrasonic impregnation, and their performance in degrading nitrobenzene within a Fenton-like system was investigated. The catalyst materials were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma mass spectrometry (ICP-MS), scanning electron microscopy (SEM), transmission electron microscope(TEM) and energy-dispersive X-ray spectroscopy (EDS). The CuO-CoO_x/SBA-15 catalysts featured well-distributed CuO-CoO_x nanoparticles within the mesoporous SBA-15 support. Compared to CuO/SBA-15 and Co₃O₄/SBA-15 catalysts with similar microstructures, the CuO-CoO_x/SBA-15 catalysts exhibited Cu-Co dual active centers and a higher abundance of redox-active sites. During catalytic degradation, H₂O₂ was continuously activated on the catalyst surface through efficient Cu⁺/Cu²⁺ and Co²⁺/Co³⁺ redox cycles. The experimental conditions (initial pH, catalyst dosage, and H₂O₂ dosage) were optimized, resulting in 99% nitrobenzene removal over a wide pH range (3.0-9.0). The primary mechanisms for the oxidation and subsequent removal of nitrobenzene in the CuO-CoO_x/SBA-15-H₂O₂ system were identified as reactions with hydroxyl radicals (·OH).