Self-Assembled 1-Octadecanethiol Membrane on Pd/ZnO for a Selective Room Temperature Flexible Hydrogen Sensor.

Pawan Pathak,Hyoung Jin Cho

doi:10.3390/mi13010026

Abstract

A layer of self-assembled 1-octadecanethiol was used to fabricate a palladium (Pd)/zinc oxide (ZnO) nanoparticle-based flexible hydrogen sensor with enhanced response and high selectivity at room temperature. A palladium film was first deposited using DC sputtering technique and later annealed to form palladium nanoparticles. The formation of uniform, surfactant-free palladium nanoparticles contributed to improved sensor response towards hydrogen gas at room temperature. The obtained sensor response was higher than for previously reported room temperature Pd/ZnO sensors. Furthermore, the use of the polymer membrane suppressed the sensor’s response to methane, moisture, ethanol, and acetone, resulting in the selective detection of hydrogen in the presence of the common interfering species. This study shows a viable low-cost fabrication pathway for highly selective room temperature flexible hydrogen sensors for hydrogen-powered vehicles and other clean energy applications.

Highlights

Hydrogen (H2 ) gas has been regarded as one of the promising next-generation cleanenergy sources because it exhibits a threefold energy density compared to that of gasoline and its combustion reaction produces water (H2 O) as the only byproduct [1,2]
This study shows a viable low-cost fabrication pathway for highly selective room temperature flexible hydrogen sensors for hydrogen-powered vehicles and other clean energy applications
The annealing of the Pd thin film under ambient conditions was studied at different temperatures

Summary

Introduction

Hydrogen (H2 ) gas has been regarded as one of the promising next-generation cleanenergy sources because it exhibits a threefold energy density compared to that of gasoline and its combustion reaction produces water (H2 O) as the only byproduct [1,2]. Compared with other sensors, such as gas chromatographies, mass spectrometers, optical, or catalytic combustion type sensors, semiconductor-based chemiresistive gas sensors are promising for practical applications due to their low-cost and scalable production methods [5,6,7,8]. The most widely used metal oxide semiconductor(MOS)-based hydrogen sensors are zinc oxide (ZnO), stannic oxide (SnO2 ), tungsten trioxide (WO3 ), titanium dioxide (TiO2 ), niobium pentoxide (Nb2 O5 ), etc. Most MOS-based hydrogen sensors have shown a limited and slow response and recovery at room temperature. For the room temperature sensing response, noble nanoparticles are often used [13]. The interaction of the hydrogen atoms on the surface of Pd is described by: Pd + H ↔ PdHx. The synthesis of metal nanoparticles is a complex process that requires toxic chemicals and requires multiple steps. Some common approaches to form metal nanoparticles are hydrothermal, electrodeposition, solvothermal, and ablation [14]

Methods

Results

Conclusion