Cu2O induced Au nanochains for highly sensitive dual-mode detection of hydrogen sulfide

Colorimetric and chemoresistive gas sensing methods have aroused great interest in H2S monitoring due to their unique merits of naked-eye readout, and highly sensitive and rapid detection. However, combining these two methods for gas detection, especially utilizing one material as their common sensing material is a grand challenge because they are inconsistent in sensing mechanism. Taking advantage of the strong chemical affinity of Cu2O for H2S and the excellent performance of localized surface plasmon resonance (LSPR) of Au nanoparticles (NPs) in the visible regions and its ability as a noble metal to enhance gas sensing property, the Cu2O-Au nanochains (NCs) were prepared for dual-mode detection of H2S gas. The Cu2O-Au chemoresistive gas sensor shows a 5-fold higher response than Cu2O sensor at room temperature with a low detection limit of 10 ppb. Such good performance is attributed to the spillover effect and catalytic activity of Au NPs, and the enhanced H2S adsorption after Au loading as revealed by density functional theory calculation. Test strips containing Cu2O-Au produced for gaseous H2S detection show superior color gradient changes (blue, yellow, and brown). Finally, the practicability of the method was validated by real-time monitoring H2S released from cell culture.