Bi₂O_2.33 Nanostructure-Based Photoanodes for Photoelectrochemical Determination of Trace Soluble Sulfides

Since soluble sulfide ions (S2–) even in low concentration can cause irreversible damage to human beings and the ecosystem, effective monitoring of S2– becomes a priority. Thus, a “signal-on” strategy for soluble sulfide detection has been designed using a Bi2O2.33 nanostructure-based photoanode. The enlarged PEC activity of nonstoichiometric Bi2O2.33 promotes the sensitivity within the detection process. The specific interaction with S2– induces the in situ formation of surface Bi2S3, which extends the light-harvesting ability and inhibits charge recombination. As a result, the PEC signal increases gradually with the increased S2–, making the selective “signal-on” strategy available. A low detection limit of 0.22 μM and superior wide linear range (1–1000 μM) are obtained, making the photoanode a potential alternative in trace sulfide monitoring.