Fluorescence of ZnO/carbon mixture and application in acid rain detection

Abstract

A ZnO and carbon nanoparticle (NP) mixture has been prepared. The fluorescence color of the mixture changes from yellow to blue when the pH value of the ambient is smaller than 5.5, which accords well with the pH standard value of acid rain (<5.6). This colorimetric change can be observed clearly by the naked eye, and thus the mixture can be employed as a probe to detect acid rain. The mechanism for the colorimetric change can be attributed to the fluorescence quenching of the ZnO NPs in acidic conditions. The results demonstrated in this paper provide a visual detection route for acid rain by the naked eye for the first time, and thus may be promising for the wide application of acid rain detection in the future.