NO2-sensing performance of SnO2 microrods by functionalization of Ag nanoparticles

Highly sensitive and selective NO2 sensing performances were realized with the networked SnO2 microrods functionalized with Ag nanoparticles by applying g-ray radiolysis. The Ag nanoparticles were transformed into nanoparticles of the Ag/Ag2O phase by thermal heating. The NO2 sensing characteristics of the Ag-functionalized SnO2 microrods were compared with those of bare SnO2 microrods. The cross-sensibility of the Ag-functionalized SnO2 microrods to other gases was tested for O-2, SO2, CO, C6H6 and C7H8. The sensing results demonstrated not only that g-ray radiolysis was an effective means of functionalizing the surface of oxide microrods with catalytic Ag nanoparticles, but also that the Ag functionalization greatly enhanced the SnO2 microrods' capability of detecting NO2 in light of response and selectivity. The special energy band structure built on the surface of SnO2 microrods associated with Ag nanoparticles leads to a superior response to oxidizing gases than reducing gases. Being combined with this, easy dissociation of NO2 into more active chemical species by the unique catalytic role of Ag is likely to be responsible for the selective, sensitive NO2 sensing performances of the Ag-functionalized SnO2 microrods.