Abstract:
Copper oxide (CuO) is a fascinating p-type semiconductor with a narrow band gap ranging from 1.2 to 2 eV, and it crystallizes in a monoclinic structure. What makes CuO especially exciting is its non-toxic nature, stability, and the fact that it is insoluble in most organic solvents—qualities that open the door to a wide range of applications. Scientists are actively exploring its potential in energy storage, photodetectors, batteries, supercapacitors, gas sensors, biosensors, nanofluids, and photocatalysis. In recent times, enhancing the optical, electrical, magnetic, and photocatalytic properties of CuO structures by doping with rare earth metals (RE) has undergone noteworthy breakthroughs. The unique properties of rare earth elements, such as gadolinium (Gd), lanthanum (La), europium (Eu), and neodymium (Nd) render them extremely useful for many advanced applications.
Considering the potential of RE elements, the specific aim of this study is to examine the impact on photocatalytic performance of undoped and Neodymium: Gadolinium (Nd:Gd) co-doped CuO nanoparticles. A set of copper oxide structures doped with different amounts of gadolinium (1, 2, and 3 mol %) and an optimal amount of neodymium (2 mol %) were synthesized using a simple hydrothermal method. The characteristics of the produced Nd:Gd co-doped CuO catalyst were investigated utilizing a range of characterization techniques. The study showed successful incorporation of Nd3+ and Gd3+ ions into the CuO structure as confirmed by the XRD and XPS analysis. The optical bandgap of the nanoparticles was determined using UV-vis spectroscopy, which demonstrates an increase in bandgap with the incorporation of Gd with 2 mol% Nd into CuO due to the presence of Gd2O3 secondary phases. To evaluate the photocatalytic efficiency, rhodamine B (RhB), an organic pollutant, was used under UV radiation. Among the various nanoparticles produced, the one with 2 mol% Nd and 3 mol% Gd demonstrated the highest photocatalytic degradation efficiency of RhB (around 85%) within just 120 minutes of exposure to UV light. The improved opto-structural and photocatalytic properties of the Nd:Gd co-doped CuO nanoparticles render them as valuable candidates for a wide range of applications, from solar cells and photocatalysts to supercapacitors, photonics, spintronics, and beyond.