Highly selective detection of sulfide through poisoning silver nanoparticle catalysts

- We develop a new analytical method for sulfide from the viewpoint of catalyst poisoning.
- Mechanism for the detection of sulfide is figured out thoroughly.
- This method is simple, highly selective and reliable.
- This method has been successfully applied to detect sulfide in real samples.
- Such a strategy can also be extended to a wide range of systems for sensing.

Catalyst poisoning often occurs in a variety of catalytic reactions, which is undesirable as it leads to a loss of catalytic activity and durability. From the viewpoint of catalyst poisoning, we herein successfully develop a facile and highly selective method for the detection of sulfide in aqueous solution, using Ag nanoparticles (AgNPs) as probes. With the addition of different amounts of sulfide into the reaction system, a series of different kinetics for catalytic reduction of 4-nitrophenol can be obtained. Mechanism studies demonstrate that the slowing down of reaction rate is owing to the surface poisoning of AgNPs, namely, the formation of a thin layer of Ag2S on the surface of AgNPs. Based on the linear relationship between the rate constant and concentration of sulfide, the quantitative determination of sulfide in a range of 500 nM − 7.5 μM has been achieved. Moreover, this analytical method shows high selectivity for sulfide beside other anions, and thus has been successfully applied in the determination of sulfide in real samples.