Nanoporous core–shell Cu@Cu2O nanocomposites with superior photocatalytic properties towards the degradation of methyl orange

Abstract

We present a facile two-step strategy to fabricate a novel nanoporous core–shell Cu@Cu₂O nanocomposite photocatalyst. The photocatalyst was synthesized via the combination of dealloying of the as-milled Al_66.7Cu_33.3 (at.%) precursor powders in alkaline media with subsequent surface oxidation in air. The microstructure of the as-prepared photocatalyst has been characterized by X-ray diffraction (XRD), a field-emission scanning electron microscope (FESEM) and a transmission electron microscope (TEM). The results show that the as-prepared photocatalyst exhibits an open, bicontinuous interpenetrating ligament (ca. 30 nm)–channel (ca. 15 nm) structure, and is comprised of Cu (core) and Cu₂O (shell) phases. Methyl orange (MO) was used as the model pollutant, and photodegradation experiments were monitored by UV-vis spectrophotometry. The nanoporous core–shell Cu@Cu₂O photocatalyst shows excellent photocatalytic activity towards the degradation of MO under sunlight. The MO degradation rate can reach as high as 8.04 mg min⁻¹ g_cat⁻¹. In addition, the influence of additive amounts of photocatalyst and initial concentrations of MO on the photodegradation process has been investigated. The photodegradation mechanism of the as-prepared photocatalyst has also been discussed.