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

Abstract

Highly sensitive and selective NO₂ sensing performances were realized with the networked SnO₂ microrods functionalized with Ag nanoparticles by applying γ-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 O₂, SO₂, CO, C₆H₆ and C₇H₈. The sensing results demonstrated not only that γ-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.