Room-temperature gas sensor based on in situ grown, etched and W-doped ZnO nanotubes functionalized with Pt nanoparticles for the detection of low-concentration H2S

Abstract

The direct in-situ growth of sensitive materials on the gas-sensing electrode is a subject of great interest for the gas-sensing field. However, combining the device design with the modification of materials is still of great challenge. Herein, a high-performance room-temperature gas sensor was constructed by functionalizing the in situ grown, etched and W-doped ZnO nanotubes (EW-ZnO NTs) with Pt nanoparticles (NPs) on new-type FTO gas-sensing electrode. The effect of etching treatment on the surface characteristics was adjusted by controlling the hydrothermal reaction time to obtain ZnO NTs with uniformly W-doped polycrystalline shells. The thus-produced EW-ZnO NTs sensor was found to be improved by 223 % in response to 10 ppm H2S at room temperature compared to the ZnO nanorods (NRs) sensor. Additionally, the effect of different Pt loading amounts on the gas-sensing performance of sensitive materials was investigated. Benefiting from the good contact of sensitive materials and gas-sensing electrodes, the formation of defects and the functionalization of noble metal Pt, the Pt@EW-ZnO NTs gas sensors exhibit numerous superior advantages, including high response, low detection limit (100 ppb) and excellent selectivity. This study shows that the gas detection capability of ZnO sensors can be significantly boosted with the in-situ growth, surface modification and noble metal functionalization, which brings insights into gas sensors.