The intrinsic oxidase-like activity of Ag2O nanoparticles and its application for colorimetric detection of sulfite

Ag2O nanoparticles (Ag2O NPs) were found to possess intrinsic oxidase-like activity and could catalyze the oxidation of typical peroxidase substrates, such as guaiacol, o-phenylenediamine (OPDA), and 3,3′,5,5′-tetramethylbenzidine (TMB), to form colored products under atmospheric O2 without addition of exogenous H2O2. Furthermore, a simple method for the colorimetric detection of sulfite was developed based on the finding that the oxidase-like activity of Ag2O NPs was inhibited by sulfite. [Display omitted] •Ag2O nanoparticles (Ag2O NPs) were found to possess intrinsic oxidase-like activity.•Ag2O NPs could catalyze the oxidation of typical peroxidase substrates under atmospheric O2 without addition of exogenous H2O2.•The presence of sulfite inhibited the color reaction of the Ag2O NPs−O2−TMB system.•A colorimetric method was established for sulfite detection.