Three-Dimensional CeO2 Nanosheets/CuO Nanoflowers p-n Heterostructure Supported on Carbon Cloth as Electrochemical Sensor for Sensitive Nitrite Detection

Abstract

Background

Nitrite is widely used as a food additive, and it is of great significance to realize accurate detection of nitrite for food safety. Electrochemical technique is characterized by simple operation and portability, which enables rapid and accurate detection. The key factors affecting the nitrite detection performance are the electrocatalytic activity and interfacial electron transfer efficiency of the electrode. The electrochemical oxidation of nitrite typically requires high potentials, posing challenges for detection. Therefore, we need to develop a high-performance sensitive electrode to fulfill the need for efficient detection of nitrite. (89)

Results

We designed a novel CeO₂ nanosheets/CuO nanoflowers p-n heterostructure supported on carbon cloth, which was used to construct an electrochemical sensor for nitrite. The p-CuO NFs/n-CeO₂ NSs heterojunction produced charge transfer effects and strong electronic interactions, which contributed to the increase in oxygen vacancies and enhanced the electrocatalytic activity. During electrochemical oxidation of nitrite, the p-n heterojunction achieved more efficient carrier separation, increasing the number of free electrons in the conduction band and facilitating charge transport. The electrode combines CuO nanoflowers with labyrinthine CeO₂ nanosheets, significantly enhancing the electrochemically active surface area and availability of active sites, improving electron conduction efficiency and improving mass transfer efficiency. The CeO₂ NSs/CuO NFs/CC showed significantly enhanced current response for the oxidation of nitrite, such as the sensitivity of 11610 μA mM⁻¹cm⁻², the linear determination range of 0.1 - 4000 μM, the LOD of 0.037 μM (S/N=3). (143)

Significance

This work combines binary metal oxide p-n heterojunction with three-dimensional morphology optimization to design sensitive electrode with enhanced nitrite sensing performance, reduced oxidation potential and improved sensitivity. And the prepared electrode can rapidly and accurately detect nitrite residues in food samples. This work provides a high-performance nitrite electrochemical sensing platform with great practical applications. (54)