Polyvinyl Alcohol-Supported AuAgNCs-CDs Film as a Selective Sensor for Gas Hydrogen Sulfide Detection in Air

A novel strategy is reported for the synthesis of glutathione (GSH)-protected bimetallic nanoclusters, Au-AgNCs@GSH, and its fabrication with polyvinyl alcohol (PVA) into a film sensor for H₂ S gas detection. Meanwhile, carbon dots (CDs) synthesized from polyethyleneimine (PEI) are introduced as an internal standard to correct the photobleaching of Au-AgNCs@GSH and uniformity of film. The joining of it greatly improves the chemical and structural stability of the composite film via multi cross-linking between PEI, PVA, and GSH. The PVA-AuAgNCs-CDs film exhibits an emission-quenching response to H₂ S gas at atmosphere, which is highly repeatable, fast, sensitive, and can distinguish H₂ S from other poisonous gases. Finally, the in-depth mechanism investigations reveal that the quenching response is attributed to decomposition of Au-AgNCs@GSH and the formation of Au₂ S and Ag₂ S in the composite film. As a sensor, the PVA-supported film combines the functions of fluorescent metal nanoclusters and polymer CDs, providing a portable device for the rapid detection of H₂ S gas in air.