Rational design of self-assembled copper oxide nanoparticles into hierarchical nanorods with high-surface-area for environmental remediation of wastewater

Abstract

The coordinated generation of hierarchical structures is a difficult task that necessitates accurate control over a number of variables such as assembly shape, array dimensions, peripheral spacing, and uniformity. In this study, we successfully synthesized self-assembled copper oxide nanomaterials using hydrothermal processes. By aggregating copper oxide nanoparticles (diameter 4–6 nm), we were able to create a hierarchical rod-like morphology with highly homogeneous particle morphology and feature sizes ranging from 50 to 200 nm. We thoroughly investigated the methods of self-assembly of CuO nanorod formations, as well as the influence of templates on the materials' structure. Our analysis included powder X-ray diffraction (XRD), TEM, N2 sorption, and X-ray photoelectron spectroscopic (XPS) methods. N2 adsorption–desorption isotherm indicated high surface areas (125–190 m2/g) and limited pore diameter (less than 5 nm) for different samples. Furthermore, XPS examination demonstrated that the materials have a high concentration of Cu2+ groups, which serve as active sites for dichromate anion adsorption. We further investigated the adsorption process using Langmuir, Freundlich and Weber–Morris models and found that these CuO nanorods can perform as a highly powerful and recyclable adsorbent for hazardous dichromate from wastewater. Our findings have significant implications for the progress of new materials for environmental remediation and other applications.