Hierarchical Co O @NiMoO core-shell nanowires for chemiresistive sensing of xylene vapor

Hierarchical Co O @NiMoO core-shell nanowires (NWs) were synthesized utilizing a two-step hydrothermal method. The NWs show a high chemiresistive response (at a temperature of 255 °C) to xylene, with an R /R ratio of 24.6 at 100 ppm xylene, while the response towards toluene, benzene, ethanol, and acetone, CO, H S and NO is much weaker. In contrast, pure Co O nanowires exhibit weak responses to all the vapors/gases and poor selectivity. The new NW sensor displays an almost linear response (1–100 ppm) to xylene and a lower detection limit of 424 ppb. The remarkable gas sensing characteristics are attributed to the synergistic catalytic effect and the formation of a heterostructure between Co O and NiMoO . [Figure not available: see fulltext.].