Electrochemical sensing based on Au particle@SiO₂@CQDs nanocomposites

In this study, carbon quantum dots (CQDs) were first synthesized using a hydrothermal method, and then, Au@SiO2 core-shell nanomaterials were synthesized using layer-by-layer assembly. CQDs were adsorbed on the surface of Au@SiO2 nanoparticles through self-assembly to form Au@SiO2/CQDs nanocomposite materials. Transmission electron microscopy and X-ray diffraction were used to characterize the size, shape, element composition, and structure of nanocomposites; ultraviolet-visible absorption spectroscopy and fluorescence spectroscopy were used to analyze the optical properties of nanocomposites. The results show that Au@SiO2/CQD nanomaterials have a core-shell structure with good morphology and exhibit excellent luminescence characteristics. The electrochemical performance of nanocomposites was characterized using electrochemical means, and a hydrogen peroxide sensor was constructed for the sensitive detection of hydrogen peroxide, thus realizing the rapid and sensitive detection of hydrogen peroxide at levels as low as 0.2 mM. The electrode GCE modified with Au@SiO2/CQDs exhibits good selectivity and stability in the detection of hydrogen peroxide.