Au@Fe2O3 nanoflowers as highly sensitive SERS substrates to detect organic pollutants in water

Noble metal aggregates have received increasing interest in environmental monitoring and biological analysis as SERS substrates due to their high sensitivity. Depositing nanoparticles onto oxide support presents an effective approach for assembling noble metals. In this study, Au@Fe2O3 composite substrates were utilized for SERS detection. Low detection limits for 4-MBA (LOD4-MBA = 4.79 x 10-9 M) and MB (LODMB = 3.36 x 10-9 M) demonstrate this SERS technique has high sensitivity. The target molecule signal did not show a significant decline, indicating good temporal stability of the substrate. The synergistic effects arising from the electromagnetic enhancement from closely spaced Au NPs, chemical enhancement from Fe2O3, and enrichment by an external magnetic field endow the Au@Fe2O3 composite substrate with outstanding SERS performance. Moreover, the Au@Fe2O3 composite substrates have been successfully used to detect 4-ATP and 4-NTP in water, which has exhibited outstanding detection capability. (LOD4-ATP = 7.25 x 10-9 M, LOD4-NTP = 1.85 x 10-9 M).