Nanoplates of α-SnWO 4 and SnW 3O 9 prepared via a facile hydrothermal method and their gas-sensing property

Abstract

Nanoplates of α-SnWO 4 and SnW 3O 9 were selectively synthesized in large scale via a facile hydrothermal reaction method. The final products obtained were dependent on the reaction pH and the molar ratio of W 6+ to Sn 2+ in the precursors. The as-prepared nanoplates of α-SnWO 4 and SnW 3O 9 were characterized by X-ray powder diffraction (XRD), N 2-sorption BET surface area, transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS). The XPS results showed that Sn exists in divalent form (Sn 2+) in SnW 3O 9 as well as in α-SnWO 4. The gas-sensing performances of the as-prepared α-SnWO 4 and SnW 3O 9 toward H 2S and H 2 were investigated. The hydrothermal prepared α-SnWO 4 showed higher response toward H 2 than that prepared via a solid-state reaction due to the high specific surface area. The gas-sensing property toward H 2S as well as H 2 over SnW 3O 9 was for the first time reported. As compared to α-SnWO 4, SnW 3O 9 exhibits higher response toward H 2S and its higher response can be well explained by the existence of the multivalent W (W 6+/W 4+) in SnW 3O 9.