Highly improved toluene gas-sensing performance of mesoporous Ag-anchored cobalt oxides nanowires

Abstract

• Ag nanoparticles were anchored on the surface of mesoporous Co 3 O 4 NWs. • Ag-loading hardly affect the morphology and microstructures of Co 3 O 4 NWs. • Ag-loading greatly improves the toluene gas-sensing performance of Ag-anchored Co 3 O 4 NWs. • The operating temperature of Ag-anchored Co 3 O 4 NWs sensors decreases from 210 °C to 190 °C. • Ag nanoparticles increase oxygen adsorption sites to reduce R a and increase interfacial R g . Mesoporous cobalt oxides nanowires (Co 3 O 4 NWs) were synthesized by the nanocasting method, and then Ag nanoparticles with the different content were anchored on the surface of Co 3 O 4 NWs. The experimental results indicate that Ag nanoparticles hardly affect the morphology and microstructure of Co 3 O 4 NWs and actually exist on the surface of Co 3 O 4 NWs. It is worth mentioning that Ag-loading greatly improves the toluene gas-sensing performance of Ag-anchored Co 3 O 4 NWs. The operating temperature of Ag-anchored Co 3 O 4 NWs sensors decreases from 210 °C for Co 3 O 4 NWs sensor to 190 °C, while the response to 100 ppm toluene gas increases 3-folds. Ag 0.166 -Co 3 O 4 NWs sensor exhibits the best gas-sensing performance due to the optimal Ag-loading content. Ag nanoparticles not only provide more effective oxygen adsorption sites to reduce resistance in air, but also form metal–semiconductor heterojunctions at the Ag/Co 3 O 4 interface to increase resistance in toluene gas. In this way, Ag-loading can further improve the gas-sensing performance of mesoporous Ag-anchored Co 3 O 4 NWs sensors to toluene gas.