Ppb-Level Selective Hydrogen Gas Detection of Pd-Functionalized In2O3-Loaded ZnO Nanofiber Gas Sensors.

Jae-Hyoung Lee,Ali Mirzaei,Jin-Young Kim,Hyoun Woo Kim,Jae-Hun Kim,Sang Sub Kim

doi:10.3390/s19194276

Jae-Hyoung Lee, Ali Mirzaei + Show 4 more

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https://doi.org/10.3390/s19194276

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Abstract

Pd nanoparticle-functionalized, xIn2O3 (x = 0.05, 0.1, and 0.15)-loaded ZnO nanofibers were synthesized by an electrospinning and ultraviolet (UV) irradiation method and assessed for their hydrogen gas sensing properties. Morphological and chemical analyses revealed the desired morphology and chemical composition of the synthesized nanofibers. The optimal gas sensor namely Pd-functionalized, 0.1In2O3-loaded ZnO nanofibers showed a very strong response to 172–50 ppb hydrogen gas at 350 °C, which is regarded as the optimal sensing temperature. Furthermore, the gas sensors showed excellent selectivity to hydrogen gas due to the much lower response to CO and NO2 gases. The enhanced gas response was attributed to the excellent catalytic activity of Pd to hydrogen gas, and the formation of Pd/ZnO and In2O3/ZnO heterojunctions, ZnO–ZnO homojunction, as well as the formation of PdHx. Overall, highly sensitive and selective hydrogen gas sensors can be produced based on a simple methodology using a synergistic effect from Pd functionalization and In2O3 loading in ZnO nanofibers.

Highlights

Hydrogen (H2 ) gas is a green, renewable, and sustainable energy source [1]
It should be noted that we studied the sensing results for the pure Pd sensor
Pd-functionalized xIn2 O3 (x = 0.05, 0.1, and 0.15)-loaded ZnO NFs were prepared for H2 gas sensing applications

Summary

Introduction

Hydrogen (H2 ) gas is a green, renewable, and sustainable energy source [1]. The main advantage of H2 is its abundance and its final combustion product being H2 O, which is again a source ofH2 [2]. Hydrogen (H2 ) gas is a green, renewable, and sustainable energy source [1]. Despite the high practicality of H2 , its flammability over a wide range of concentrations (4%–75%) and an auto-ignition temperature of 250–400 ◦ C makes it extremely dangerous [3]. It is a colorless, odorless, and tasteless gas that cannot be detected by human senses [4]. During storage, transport and use, an unexpected leakage of hydrogen can be catastrophic. As the use of hydrogen is becoming increasingly commonplace in different industries, the early detection of hydrogen gas using gas sensors is of prime importance [5]

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