Enhancing an in situ-grown Ag/Cu2O/copper foam SERS substrate via an electromagnetic–chemical synergistic mechanism for trace detection of organic dyes

Abstract

Organic pollutants pose a significant threat to the ecological environment and human health. Surface-enhanced Raman spectroscopy (SERS) is widely used as a non-destructive and highly sensitive technique for trace analysis of organic pollutants. Herein, a self-supported three-dimensional (3D) Ag/Cu₂O/copper foam (CF) SERS substrate with a CF skeleton was synthesized via high-temperature calcination and in situ growth. Meanwhile, the substrate synergistically improved the performance of the SERS substrate by combining an electromagnetic and chemical mechanism. It has a limit of detection (LOD) of 10⁻⁸ M for rhodamine 6G (R6G) (10⁻³ M for the Cu₂O/CF substrate and 10⁻⁷ M for the Ag/CF substrate) and an enhancement factor of 5.83 × 10⁶, exhibiting a signal attenuation of only 26% after 30 days of exposure to the natural environment. Additionally, the substrate has a LOD of 10⁻⁸ M for crystal violet (CV) in neutral industrial wastewater and 10⁻⁷ M for CV in acidic and basic (pH = 5, 9) industrial wastewater because different acid–base conditions affect the CV molecule. Therefore, the prepared three-dimensional self-supporting Ag/Cu₂O/CF SERS substrate shows promising prospects for detecting organic dyes in industrial wastewater.