Highly selective, sensitive, and visible detection of fluoride ions through transforming their roles from reactants to catalysts in the silicon corrosion reaction

Abstract

On-site and visual detection of fluorine ions at high selectivity and sensitivity in a water phase is highly anticipated. This work proposes a new mechanism for colorimetric fluorine detection at high selectivity and sensitivity in an aqueous phase based on silicon nanoparticles (SiNPs). The specific silicon corrosion reaction provides the detection with high selectivity and anti-interference properties. The strategy that transforms the role of fluoride ions from reactants into catalysts at elevated temperatures eliminates the concentration requirement of fluoride ions in the silicon corrosion reaction and greatly improves the sensitivity of fluoride ion detection. Under optimal conditions, the limit of detection (LOD) is calculated as 0.11 ppm. Moreover, this strategy enables visual distinguishing of the fluorine content in water samples on the order of ppm, and its comparison with the sewage discharge standard (10 ppm) and the drinking water standard (1 ppm). In a broader context, our approach is likely to enable plausible, convenient and cost-effective fluorine detection in drinking water and industrial waste water. Furthermore, the strategy to transform the role of analytes from reactants into catalysts may shed light on the design of highly sensitive sensing systems based on chemical reactions.