Colorimetric/SERS Dual-Mode Detection of Mercury Ion via SERS-Active Peroxidase-Like Au@AgPt NPs

•A novel colorimetric/SERS dual-mode detection of Hg2+ was proposed by using SERS-active peroxidase-like Au@AgPt NPs.•The dual-mode probe integrates the advantages of facile detection by colorimetric analysis and high-sensitive trace assay by SERS.•The limit of detections (LODs) of colorimetric analysis and SERS assay were 0.52 μM and 0.28 nM, respectively.•The dual-mode detection has the characteristic of fast, on-site, specificity, high sensitivity, and wide detection range for Hg2+ assay.