An Affordable Amperometric Gas Sensor Based on Polyvinylidene Fluoride Solid-State Electrolyte for Highly Selective Detection of ppm-Level H₂ at Room Temperature

Abstract

Currently, the assessment of irritable bowel syndrome (IBS) through the detection of H 2 levels in exhaled breath using commercial gas sensors remains a challenging task. In this work, we presented a cost-effective amperometric gas sensor capable of monitoring parts per million-level H 2 at room temperature by grafting polystyrene sulfonic acid onto polyvinylidene fluoride (PVDF-g-PSSA), creating a thermal stable and highly adaptable solid polymer electrolyte. This PVDF-g-PSSA exhibited a high tensile stress value of 9.72 MPa and ionic conductivity of 2.73 × 10 −2 S cm −1 , which is comparable with that of the Nafion N115 membrane. The amperometric gas sensor based on the PVDF-g-PSSA membrane exhibited preferable sensing performance, including a response current of 174.3 nA to 50 ppm of H 2 at room temperature and 50% relative humidity. Additionally, it also displayed an acceptable response−recovery time of 96 and 54 s, limit of detection (LOD) of 1 ppm H 2 , and selectivity for H 2 over other interfering gases. Remarkably, this sensor demonstrated a highly linear relationship (4.6 nA/ppm H 2 ) with a correlation coefficient of 0.9998. Furthermore, we also applied this sensor to distinguish parts per million-level H 2 concentrations in simulated exhaled breath. These findings demonstrated an affordable amperometric H 2 gas sensor for detecting ppm-level H 2 at room temperature, even without requiring a bias, thereby promising for biomarker detection in exhaled breath.