Transformation of Nanostructures Cu₂O to Cu₃Se₂ through Different Routes and the Effect on Photocatalytic Properties

Abstract

In this work, copper selenide (Cu 3 Se 2 umangite phase) was synthesized by two routes, using a chemical reaction and the hydrothermal method to obtain CuSe-A and CuSe-H, respectively. The synthesis of Cu 3 Se 2 consisted of a three-step process: in the first step, copper(I) oxide hexapods (Cu 2 O) were obtained as the copper reservoir; in the second step, selenium ions were obtained from the reduction of selenium powder; and in the third step involves mixing two precursors following the two synthesis routes mentioned before. Analysis of X-ray diffraction and X-ray photoelectron spectroscopy showed the formation of the Cu 3 Se 2 phase by both synthesis routes. On the other hand, using the scanning electron microscopy (SEM) technique, it is observed that the Cu 3 Se 2 sample (CuSe-A) is obtained by exchanging in solution with agitation and that the copper selenium phase grows only on the surface of the hexapods. Meanwhile, the hydrothermal route promotes a total conversion of copper(I) oxide hexapods to the copper selenide phase (CuSe-H). The resulting materials were tested as photocatalytic materials to remove methylene blue dye in water under sunlight irradiation. Cu 3 Se 2 (CuSe-H) obtained by the hydrothermal route exhibited a higher efficiency of photodegradation of dye, reaching a removal percentage of 92% after 4 h under sunlight.

Selenium Nanocomposites in Natural Matrices as Potato Recovery Agent

“…In addition, XPA was used to characterize the NCs, which has high accuracy and does not affect stability of prepared samples. This method is used not only for the study of chemical objects including Se-containing samples [ 21 ], but also for various purposes in geology [ 22 ], biology [ 23 ], and medicine [ 24 ]. XPA is also attractive because its ability to detect structures that are invisible with X-ray absorption imaging.…”

Predictive Synthesis of Copper Selenides Using a Multidimensional Phase Map Constructed with a Data-Driven Classifier

“…Berzelianite Cu 2– x Se forms under oleylamine-poor reaction conditions when using Ph 2 Se 2 , whereas umangite Cu 3 Se 2 forms under more oleylamine-rich reaction conditions (Figure b). This is counterintuitive since the more reducing conditions introduced with greater volumetric ratios of oleylamine result in Cu 3 Se 2 , which formally contains Cu 2+ , although we should note that other studies have assigned copper as being monovalent with the oxidation state of selenium being −3/2 . Nonetheless, this highlights the value of using such phase maps and the information they can provide.…”