Gasochromic WO3 Nanostructures for the Detection of Hydrogen Gas: An Overview

Abstract

Hydrogen is one of the most important gases that can potentially replace fossil fuels in the future. Nevertheless, it is highly explosive, and its leakage should be detected by reliable gas sensors for safe operation during storage and usage. Most hydrogen gas sensors operate at high temperatures, which introduces the risk of hydrogen explosion. Gasochromic WO3 sensors work based on changes in their optical properties and color variation when exposed to hydrogen gas. They can work at low or room temperatures and, therefore, are good candidates for the detection of hydrogen leakage with low risk of explosion. Once their morphology and chemical composition are carefully designed, they can be used for the realization of sensitive, selective, low-cost, and flexible hydrogen sensors. In this review, for the first time, we discuss different aspects of gasochromic WO3 gas sensor-based hydrogen detection. Pristine, heterojunction, and noble metal-decorated WO3 nanostructures are discussed for the detection of hydrogen gas in terms of changes in their optical properties or visible color. This review is expected to provide a good background for research work in the field of gas sensors.

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

“…On the other hand, despite the high practicality of H 2 , its flammability over a wide range of concentrations (4%–75%) and an auto-ignition temperature of 250–400 °C makes it extremely dangerous [3]. Furthermore, it is a colorless, odorless, and tasteless gas that cannot be detected by human senses [4]. Accordingly, during storage, transport and use, an unexpected leakage of hydrogen can be catastrophic.…”

Using smart glazing for reducing energy consumption on existing office building in hot dry climate

“…The color of the glass becomes dark when exposed to low concentration hydrogen, and transparent when exposed to oxygen [13]. GC is suitable for large glazing building facades implementation due to its advantage as it has a simple configuration and low cost [14].…”

Characteristics of Highly Sensitive Hydrogen Sensor Based on Pt-WO3/Si Microring Resonator

“…They can provide good reliability because of their immunity to electromagnetic interferences and their explosion-proof structures that have no electrical contacts. Optical hydrogen sensors using optical fibers and nanostructures have been developed [15][16][17][18][19], and hydrogen gas with a concentration as low as 0.1 vol% has been detected [2].…”

“…In this study, we have investigated a highly sensitive silicon-on-insulator (SOI)-MRR-based hydrogen sensor with Pt-doped tungsten oxide (WO 3 ) with high sensitivity and rapid response. WO 3 tis a suitable material for hydrogen gas sensing [19]. When hydrogen gas is exposed to a WO 3 film, WO 3 reacts with hydrogen atoms to form tungsten bronze (H x WO 3 ).…”

“…As a result, the optical properties of the film, such as the absorption coefficient and refractive index, change, and transmittance of light also changes. Many of the optical hydrogen gas sensors with WO 3 use these effects [15,16,19,28]. On the other hand, the proposed silicon (Si)-MRR-based hydrogen sensor uses the exothermic reaction in the WO 3 film.…”