General fabrication and enhanced VOC gas-sensing properties of hierarchically porous metal oxides

Abstract

A facile and general route to synthesize hierarchically porous metal oxide nanostructures was reported here. The results indicate that the hierarchically porous metal oxides show high sensitivity to toxic or dangerous gases. The signal sensitivity of the gas sensors exhibits a good linear relation with the VOC gas concentration. As one of the as-synthesized hierarchically porous metal oxides, ZnO exhibits the lowest detection limit of 15 ppb for formaldehyde, which is much lower than the limit value of indoor formaldehyde (60 ppb). Furthermore, the sensitivity of the ZnO porous nanosheets decorated with Au nanoparticles is 10 ppb for formaldehyde, which is about 1.5 times higher than that of the unmodified ZnO porous nanosheets.