In Situ Growth of Cu/CuO/Cu₂O Nanocrystals within Hybrid Nanofibers for Adsorptive Arsenic Removal

Abstract

Nanomaterials such as copper nanoparticles have attracted significant attention because of their interesting size-and shape-dependent properties. However, their increased instability remains a challenge. This study therefore focuses on the growth of copper/copper oxide nanocrystals within nanofiber scaffolds, achieved by thermal reduction of poly(vinyl alcohol) nanofibers cross-linked with copper(II) acetate. A reduction temperature of up to 800 °C in 15% H 2 balanced in N 2 was found to lead to the formation of copper-based nanofibers (CuNFs) of sub-250-nm diameter that presented a core−sheath morphology, resulting from copper efflorescence. Enrobing a hydrolysis-resistant polymer core, the sheath layer was found to be composed of a discrete distribution of polymer-embedded crystalline nanospheres with diameters below 20 nm and of round crystallites of up to 65 nm protruding at the surface of CuNFs. With a significant proportion in copper intermediary states, this heterogeneous material is promising for various applications benefiting from the surface reactivity and versatile efficiency from the simultaneous presence of a transition metal and transitionmetal oxide. For instance, with a material dose of 0.20 g•L −1 and an initial arsenic(V) concentration of 120 mg•L −1 , CuNFs yielded up to 96.5% arsenic(V) removal. This route for the manufacture of copper hybrid nanofibers can be adapted to other transition metals and blends.

Monolithic Cu2O-CuO/Cu Mesh Catalyst for Ambient Ozone Removal

“…There is no direct method to grow Cu 2 O NWs on a Cu substrate, so the Cu 2 O NWs are obtained by reducing the oxidized sample O 2 -350-3 h in the atmosphere of Ar/H 2 (5%). Meanwhile, CuO prefers to be reduced to Cu directly rather than Cu 2 O . The apparent activation energy of reduction of Cu 2 O to Cu is 27.4 kcal mol ‑1 , which is higher than that of reduction of CuO to Cu of 14.5 kcal mol ‑1 .…”

“…Meanwhile, CuO prefers to be reduced to Cu directly rather than Cu 2 O. 30 The apparent activation energy of reduction of Cu 2 O to Cu is 27.4 kcal mol -1 , which is higher than that of reduction of CuO to Cu of 14.5 kcal mol -1 . Thus, CuO tends to be reduced to Cu rather than Cu 2 O under a sufficient amount of H 2 atmosphere.…”

Amorphous Alumina Thin Films Deposited on Carbon Microfibers As Interface Layer for Thermal Oxidation Barriers

“…Samples for TEM were prepared by thermal degradation of the carbon microfiber in air at 975 K, followed by ultrasonication of the aluminum oxide films and casting on a TEM carbon lacey 300 nm mesh grid. This procedure is reported elsewhere …”

“…This procedure is reported elsewhere. 25 4D scanning transmission electron microscopy (4D-STEM) was performed with the camera RIO 16IS equipped with Digiscan III. The camera length was 20 cm, spot size 1 nm, and condenser aperture 10 μm.…”

Photoactivation of peroxymonosulfate (PMS) over a CuO–ZnO p–n heterojunction for the selective C2 trimerization of indoles

“…34 The intense peak at 529.6 eV for CuO and CuO-ZnO materials was attributed to lattice oxygen. 35 The peak at 531.6 eV for all the three materials originated from the oxygen defects/vacancies within the matrix. 34 Each of the aforementioned XPS peaks was fitted with respect to the C 1s peak, which had binding energies of 288.8 eV (CO), 286.0 eV (C-O), and 284.7 eV (C-C) (Fig.…”