Nanoscale Ag-Decorated Hollow Porous CuO/SnO2 Heterojunctions for Isopropanol Detection

Nanoscale Ag-decorated CuO/SnO2 heterojunctions with coralloid hollow porous structure (ACSO HPs) were successfully synthesized though a hydrothermal route with electroless Ag plating followed by the calcination and acid-washing. Detailed microstructural characterizations confirmed that the hollow porous structure comprised CuO/SnO2 and Ag/SnO2 nanoheterojunctions, and the SnO2 surface was decorated primarily with nano-Ag, which was the outer layer of the structure. The ACSO HPs sensor displayed a higher response to isopropanol compared to toluene, acetone, benzene, ethanol, and methanol than other samples. For 100 ppm isopropanol, the ACSO sensor exhibited a faster response time (6 s) and a higher recovery time (34 s) than undecorated Ag samples. The improved sensing performance of ACSO samples was ascribed to the synergistic effect of the CuO/SnO2 nanoheterojunctions with the dramatic sensitization of the decorated nano-Ag, as well as the HPs.