Synthesis and Catalytic Performance of Cu-CeO2 Nanoparticles and the Application in Cr(VI) Detection: Third-Year Undergraduate Comprehensive Laboratory Experiment

Nanozyme is a kind of mimetic enzyme possessing unique properties of nanomaterials and catalytic functions of natural enzymes. The nanozymes have the characteristics of high catalytic efficiency and good stability and are widely utilized in medicine, chemical industry, food, agriculture, and environment. This laboratory experiment is designed for third-year undergraduate students who have a background in chemistry or material science. The experiment involves the synthesis, characterization, catalytic performance, and application of copper doped cerium oxide nanoparticles (Cu-CeO₂ NPs), which contain both CuO and CeO₂. The required raw materials for the experiment are readily available, and the synthesis process is safe and simple. The nanomaterials are characterized via transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV–vis spectroscopy. The experiment also involves studying the peroxidase (POD)-like activity of Cu-CeO₂ NPs, which catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) into its oxidation state in the presence of H₂O₂. In the presence of Cr(VI), the Cu-CeO₂ NPs-based colorimetric reaction was enhanced and also increased with the concentration of Cr(VI). This can be used for the sensitive detection of Cr(VI), which was much better than that without Cu-CeO₂ NPs. This laboratory experiment provides the third-year undergraduates with a chance to enhance their knowledge in advanced nanomaterials and modern characterization instruments. Additionally, it helps students to develop their hands-on operation skills, team cooperation ability, and the ability to integrate theory with practice.