A trace ppb-level electrochemical H2S sensor based on ultrathin Pt nanotubes

An amperometric sensor has been developed with high sensitivity for real-time measurement of H 2 S gas at room temperature (25 °C ± 2 °C). In order to enhance the utilization of platinum and improve its catalytic performance, an ultrathin and one-dimensional (1D) Pt nanotubes (Pt NTs, ~3.5 nm in wall thickness) were designed and used as sensing electrode materials . Different concentrations of H 2 S gas were tested to evaluate the sensitivity of the sensor and to obtain the relationship between the electricity response signal and H 2 S gas concentration. At room temperature, the sensor based on Pt NTs shows better sensing performance than that based on Pt nanoparticles , which is mainly attributed to two factors, namely, the inherent characteristic of the hollow 1D Pt NTs. The Pt NTs-based sensor shows a detection limit as low as 0.025 ppb, which are the lowest among H 2 S gas sensors reported in the literatures. The response and recovery times are 0.75 s and 0.86 s for 0.8 ppb H 2 S, respectively. In addition, the sensor shows a wide range (100 ppm-0.025 ppb), high selectivity compared to other gases (including CO, NH 3 , CH 2 O, NO and NO 2 ), good reproducibility, and satisfactory long-term stability. Thus, the ultrathin Pt NTs-based gas sensor would be a great potential to the real-time and online monitoring of the trace ppb-level H 2 S gas at room temperature.