Quasi-fuel-cell type gas sensor incorporating Pt/Nafion/MnO2 composite membrane electrode for hydrogen detection at room temperature

Hydrogen sensor based on proton exchange membrane fuel cells (PEMFCs) was one of the most extensively studied types. However, traditional Pt/C based electrodes suffered from several drawbacks, including high cost, low catalytic efficiency for oxygen reduction reaction (ORR) and slow reaction kinetics. Herein, we developed a quasi PEMFCs hydrogen sensor utilizing MnO 2 as cathode catalyst, where the electrochemical signal was generated via the direct MnO 2 redox reaction with hydrogen, replacing the ORR process. Membrane electrode assemblies (MEAs) were successfully fabricated incorporating α-MnO 2 , β-MnO 2 , and δ-MnO 2 polymorphs. The β-MnO 2 -based sensor demonstrated best sensing performance with a maximum sensitivity of 96 nA/ppm, a 34-fold enhancement over conventional dual-platinum electrochemical sensors, under the optimized volume ratio of catalyst ink (ethylene glycol: Nafion solution: water = 1:4:4). Moreover, the β-MnO 2 -based sensor exhibited significantly superior response and recovery speed. This strategy provided an effective approach for the commercialization of next generation PEMFCs-type hydrogen sensors.