Ultrasensitive and Reusable SERS Substrates Based on Ag-Photodecorated Mn2O3 Microspheres for Nitrofurazone Detection

A micro/nanocomposite of metal-oxide semiconductor decorated with noble metal has great potential in surface enhanced Raman spectroscopy (SERS) due to the abundant analyte adsorption and the synergistic utilization of charge transfer and electromagnetic mechanisms. Herein, a Mn2O3/Ag micro/nanocomposite is presented by decorating hydrothermally synthesized Mn2O3 microspheres with photoreduced Ag nanoparticles (NPs) for ultrasensitive detection of nitrofurazone (NFZ). The loading amount of Ag NPs on Mn2O3 microspheres is optimized to obtain the utmost Raman signal enhancement. The reusability of SERS substrates is achieved by the photolysis capability of the Mn2O3/Ag micro/nanocomposite for NFZ molecules under ultraviolet irradiation. The excellent SERS performance of the Mn2O3/Ag micro/nanocomposite is demonstrated by an enhancement factor of 2.05 × 1012 and an ultralow limit of detection of 7.39 × 10–13 M for NFZ detection. The relative standard deviation of Raman signal intensities less than 7% shows the uniform and reproducible nature of the Mn2O3/Ag-based SERS substrate. The practical analysis of NFZ spiked in the chicken meat solution reveals the recovery values from 86.5 to 98.7%. The retention rate of 92.22% after the fifth photodegradation cycle proves its excellent reusable capability. The performance analysis of Mn2O3/Ag-based SERS substrates indicates the bright prospect for their utilization in real sample analysis.