Au Decorated Zinc Oxide Nanowires for CO Sensing

We present the room temperature detection of carbon monoxide using Au decorated zinc oxide (ZnO) nanowires. Zinc oxide nanowires were grown via the vapor liquid solid method whereas the gold nanoparticles were prepared by the solution growth method. The surface of the ZnO nanowires was decorated by Au nanoparticles. Gas sensing properties of such nanowires were studied at room temperature for various concentrations of CO (100 to 1000 ppm) in synthetic air. Enhancement in gas sensing response by Au decoration on ZnO nanowires was observed. Au nanoparticles act as a catalyst in chemical sensitization and improve the reaction and response time. The improvement in gas sensing behavior is attributed to the change in conductivity of the metal decorated ZnO nanowires on CO exposure due to the transfer of electrons resulting from gas oxidation at the ZnO nanowire surface.