PtCu3 excavated rhombic dodecahedral nanocrystals with excellent peroxidase-like activity for highly sensitive colorimetric sensing of nitrite.

Abstract

Nanozymes have emerged as a forefront area in analytical sensing research, especially for the sensitive detection of nitrite, which is essential for human health. We synthesized PtCu3 rhombic dodecahedral nanocrystals (ERD NCs) via a two-step Cu-seeding method. TEM confirms that these NCs are consist of ultra-thin nanosheets with a thickness of approximately 2.8 nm, resulting in higher atomic utilization efficiency. Kinetic tests reveal that PtCu₃ ERD NCs exhibit excellent peroxidase-like activity. XPS valence band spectra demonstrate that the formation of the alloy causes a shift in the d-band center, which significantly facilitate the adsorption of H2O2 and its decomposition into hydroxyl radicals. Based on these findings, we have developed a colorimetric platform for the quantitative detection of nitrite. This platform can effectively detect nitrite in the concentration range of 5-500 μM in real samples, which is of great value for the detection of nitrite in food.