Oxygen-vacancy-enhanced Catalytic Activity of Au@Co3O4/CeO2 Yolk-shell Nanocomposite to Electrochemically Detect Hydrogen Peroxide |
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Authors: | Lingli Lei Yuanyuan Zhang Ying Jiang Lulu Xiong Yingshuai Liu Chang Ming Li |
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Affiliation: | 1. Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education, School of Materials and Energy, Southwest University, Chongqing, 400715 P. R. China Equal contribution to this work.;2. Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education, School of Materials and Energy, Southwest University, Chongqing, 400715 P. R. China |
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Abstract: | Biomimetic electrochemical sensors are very promising not only due to their lower expense and longer stability than conventional enzymatic ones, but they also often suffer from simultaneously achieving high sensitivity and good selectivity. Here we present a well-defined Au@Co3O4/CeO2 yolk-shell nanostructure (YSN) that is first synthesized and exploited as highly efficient electrocatalysts for hydrogen peroxide (H2O2) detection. The introduced CeO2 in Co3O4 matrix greatly facilitates the migration of lattice oxygen, which increases the concentration of surface oxygen vacancies (Oa), remarkably enhancing the adsorption ability of H2O2 and promoting the decomposition of H2O2 for faster electron transfer than pristine Au@Co3O4 core-shell nanostructure (CSN). The abundant Oa of Au@Co3O4/CeO2 YSN is confirmed by X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR). The as-prepared biomimetic sensor delivers a wide dynamic range (5.0 nM to 5.4 μM), a low limit of detection (LOD) (2.74 nM), and a high sensitivity (35.67 μA μM−1 cm−2), paving a new way to construct an ultrasensitive and selective enzyme-free biomimetic electrochemical sensor. Furthermore, the sensor is used to real-time monitor H2O2 released from human cervical cancer cells (HeLa) and human umbilical vein endothelial cells (HUVEC), demonstrating its great potential in practical applications. |
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Keywords: | Au@Co3O4/CeO2 YSN Oxygen vacancies Adsorption Biosensor |
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