Selective C2H2 detection with high sensitivity using SnO2 nanorod based gas sensors integrated with a gas chromatography

We report on the sensitive and selective sensing properties of SnO2 nanorods (NRs) based gas sensors coupled with a miniature gas chromatography (mini-GC) system for the detection of acetylene. The SnO2 NRs were fabricated by a glancing angle deposition (GLAD) method and their average height and diameter were similar to 200 nm and similar to 30 nm, respectively. In order to overcome a selectivity issue of metal oxide semiconductor gas sensors, we integrated our SnO2 NRs based sensors with a packed column. The device accurately and selectively detected acetylene within 2 min (similar to 120 s). We found that loading a thin layer (5 nm) of metal catalysts such as Au, Pt or Pd increases the sensing abilities of the SnO2 NRs sensors. Among the tested sensors, the Pd-coated SnO2 NRs sensor (Pd-SnO2 NRs) exhibited the best sensing performance for the detection of 10 ppm of acetylene and the lower detection limit of 0.01 ppm. The superior sensing properties of Pd-SnO2 NRs are due to the large amount of oxygen deficiencies on the surface of Pd-SnO2 NRs, which acts as reactive sites. More importantly, the mini-GC device can be used to selectively detect 10 ppm of acetylene from other gases such as H-2. Our findings demonstrate that Pd-SnO2 NRs integrated with a mini-GC device can be utilized to monitor the dissolved acetylene gas in transformer oil in real time.