Highly Sensitive and Selective Detection of Hydrogen Using Pd-Coated SnO 2 Nanorod Arrays for Breath-Analyzer Applications.

We report a breath hydrogen analyzer based on Pd-coated SnO 2 nanorods (Pd-SnO 2 NRs) sensor integrated into a miniaturized gas chromatography (GC) column. The device can measure a wide range of hydrogen (1-100 ppm), within 100 s, using a small volume of human breath (1 mL) without pre-concentration. Especially, the mini-GC integrated with Pd-SnO 2 NRs can detect 1 ppm of H 2 , as a lower detection limit, at a low operating temperature of 152 °C. Furthermore, when the breath hydrogen analyzer was exposed to a mixture of interfering gases, such as carbon dioxide, nitrogen, methane, and acetone, it was found to be capable of selectively detecting only H 2 . We found that the Pd-SnO 2 NRs were superior to other semiconducting metal oxides that lack selectivity in H 2 detection. Our study reveals that the Pd-SnO 2 NRs integrated into the mini-GC device can be utilized in breath hydrogen analyzers to rapidly and accurately detect hydrogen due to its high selectivity and sensitivity.