For instance, BSA-Au NCs [21], DNA-Au/Ag NCs [22],GSH-Ag NCs [23], DNA-Cu NCs [24] have been utilized directly for fabricating S2−sensors on the basis of fluorescence quench-ing. A new colorimetric strategy for detecting S2−has emerged recently based on gold nanoparticles (Au NPs) by taking advantage of their unique chemical, electrical, optical and catalytic properties [25–27]. A colorimetric assay for S2−has been developed based on color variation of GSH-Au NPs corresponding to the change from dispersed state to aggregated state [25]. The specific suifide-for-GSH ligand exchange reaction led to high selectivity but low sensitivity. The sensitivity was improved significantly by employing peroxidase-like activity of bare Au NPs through amplification effect of the catalytic reaction [26]. Additionally, colorimetric sensing assays for S2−based on anti-aggregation or re-dispersion ofAuNPs are good alternatives to improve the sensitivity and selectivity [28]. These optical sensors have made great contributions in S2−sensing. Unfortunately, preparation of organic fluorescentprobes or nanomaterials, and additional treatments such as separation, modification and purification, which are complicated and time-consuming, are essential for this process. Therefore, simple and efficient methods for S2−detection with high sensitivity and selectivity are still highly desired.