Au NPs@NC@MnO2 with exceptional nano-enzyme activity for sensitive colorimetric detection of Cr (VI)

In this study, a highly sensitive colorimetric sensor was established for the detection of Cr (VI) in water using Au NPs@NC@MnO2 based on signal amplification. Au NPs@NC@MnO2 exhibited excellent nano-enzyme activity and catalyzed the oxidation of TMB during detection of Cr (VI) in the linear range of 0.80 to 160.26 nM at limit of detection of 0.73 nM (S/N = 3). The valence states of Au and Mn change before and after the reaction, as a result Au NPs@NC@MnO2 promotes the electron transfer between Cr (VI) and TMB. The colorimetric sensor of Cr (VI) based on Au NPs@NC@MnO2 also exhibits excellent selectivity for interference ions. Moreover, the developed assay has been successfully applied to detect Cr (VI) in real samples. This study demonstrated that Au NPs@NC@MnO2 is simply designed, high sensitivity and selectivity in colorimetric detection of Cr (VI), which could be useful for the field detection of Cr (VI).

Automated summary

A highly sensitive colorimetric sensor based on Au NPs@NC@MnO2 was developed for the detection of Cr (VI) in water. The sensor exhibited excellent selectivity and detection performance, and was successfully applied to real samples.