Planar solid-state amperometric hydrogen gas sensor based on Nafion®/Pt/nano-structured polyaniline/Au/Al2O3 electrode

The effects of Nafion® film thickness and charges passed for the preparation of Pt and nano-structured polyaniline (nsPANi) on the sensing properties of a planar solid-state amperometric hydrogen gas sensor are investigated. The surface morphology, Pt loading and electroactive surface area (ESA) are analyzed by FESEM, inductively coupled plasma (ICP) and cyclic voltammetry (CV), respectively. The specific sensitivity of the hydrogen gas sensor can be effectively promoted by decreasing the thickness of the Nafion® film and the charge passed for the electrodeposition of Pt and PANi (from 30 to 10 mC), respectively. The very low Pt loading of the sensing composite electrode is due to the use of the nanofibrous PANi as support, which remarkably promotes Pt utilization. The specific sensitivity and the response time of the hydrogen gas sensor based on the Nafion® (5.7 μm)/Pt/nsPANi/Au/Al2O3 electrode with a Pt loading of 1.87 μg are found to be 338.50 μA ppm−1 g−1 and 100-250 s, respectively, for measuring 10-10,000 ppm H2.