Synergistic function of Au NPs/GeO2 nanozymes with enhanced peroxidase-like activity and SERS effect to detect choline iodide

A novel Au NPs/GeO 2 nanozymes are developed as Surface-Enhanced Raman Scattering (SERS) substrates with the promising prospect for detection ChI. Herein, it is discovered that both Au NPs and GeO 2 nanozymes have peroxidase-like activity, catalyzing colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to produce blue TMB ox . Interestingly, compared with single Au NPs or GeO 2 nanozymes, the Au NPs/GeO 2 nanozymes show stronger peroxidase-like activity, and significantly ameliorated SERS signal of TMB ox . The mentioned two enhancements are ascribed to a positive synergistic function of Au NPs/GeO 2 nanozymes. Surprisingly, choline iodide (ChI) can inhibit the positive synergy in Au NPs/GeO 2 nanozymes, and slow down the reaction of TMB-H 2 O 2 -Au NPs/GeO 2 system. On this foundation, a new Au NPs/GeO 2 SERS technique with high sensitivity, label-free detection method of choline iodide (ChI) is established, suggesting that Au NPs/GeO 2 nanozymes have the potential application of water environment.