High-efficiency Cu2O/CuFe-LDH nanocomposite for Fenton degradation of organic pollutants: Boosted dual redox cycles

Abstract

The incorporation of dual redox sites within catalytic materials for H₂O₂ activation represents a promising approach to enhance the efficiency of pollutant decomposition. In this study, Cu₂O modified CuFe-LDH nanocomposite (Cu₂O/CuFe-LDH) was successfully synthesized via in situ topotactic transformation of CuFe-LDH. The catalytic degradation performance of the Cu₂O/CuFe-LDH nanocomposite was investigated utilizing tetracycline hydrochloride (TCH) as a typical antibiotic contaminant. It demonstrated exceptional catalytic activity, achieving a TCH elimination rate of 93.0 % in 60 min. A rate constant value of 0.0426 min⁻¹ was calculated for the pseudo-first-order kinetic model, which was 1.6 times and 5.0 times higher than those of CuFe-LDH and Cu₂O, respectively. Moreover, the Cu₂O/CuFe-LDH nanocomposite demonstrated remarkable cycling stability (85 % degradation rate after 5 recycling cycles), a wide pH range (3−11), resistance to background ion interference, and lower toxicity of the products of degradation. Based on radical scavenger tests and electron paramagnetic resonance (EPR) spectroscopy, it was verified that TCH degradation was mediated by ¹O₂, •OH and •O₂^-, with ¹O₂ playing an essential role. X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) investigations indicate that the remarkable catalytic efficacy of Cu₂O/CuFe-LDH is predominantly due to the synergistic interactions between Cu₂O and CuFe-LDH, with Cu₂O promoting the accelerated dual Cu²⁺/Cu⁺ and Fe³⁺/Fe²⁺ cycling. Thus, the Cu₂O/CuFe-LDH nanocomposite exhibits exceptional efficiency, environmental friendliness and recyclability, rendering it an ideal candidate for practical wastewater treatment applications.