Catalytic degradation of 4-nitrophenol and methylene blue using ceria-coated gold nanoparticles as a dual-functional...

A structurally tunable and morphologically homogeneous core/shell nanocatalysts of cerium dioxide-coated gold nanoparticles (AuNPs@CeO₂) were successfully prepared. By investigating AuNPs@CeO₂ with different CeO₂ shell layer thicknesses on the hydroreduction of 4-nitrophenol (4-NP), as well as probing the optimal photocatalysis of AuNPs@CeO₂ at different irradiances and methylene blue (MB) concentrations, the optimal thicknesses of AuNP-covered CeO₂ layers were identified as 16.43 ± 1.17 nm. AuNPs@CeO₂ exhibited excellent catalytic performance for both heterogeneous catalytic degradation of 4-NP and photocatalytic degradation of MB. With the addition of 50 μL of AuNPs@CeO₂, the normalized apparent rate constant reached 3.145 × 10⁴ min^-1 mmol^-1, and the optimal degradation rate of methylene blue (MB) reached 99.2% with the addition of 0.5 mL of AuNPs@CeO₂. This not only provides a novel nanocatalyst for the efficient degradation of organic pollutants, but also provides a new research idea and theoretical basis for the design and development of composite functional materials.