Nano-Columnar High-Sensitivity Gasochromic Hydrogen Sensor for Low-Concentration Leak Detection

Hydrogen (H2), known for its clean nature, high energy density, and renewability, is widely utilized in diverse fields including energy transport, the chemical industry, metallurgy, and aerospace. However, hydrogen poses a significant safety risk due to its flammability when its concentration in air exceeds 4%, making reliable leak detection essential. In this study, we present a highly responsive and efficient gasochromic hydrogen sensor designed to detect low-concentration hydrogen leaks through visible color changes. The sensor fabrication involves depositing a porous nanocolumnar amorphous WO3 layer onto glass particles, followed by the deposition of nanosized Pd particle, which serve as catalysts for H2 dissociation. To enhance durability and stability, the device is encapsulated with a PDMS coating. Comprehensive characterization of the structural, chemical, and optical properties of the WO3–Pd sensor demonstrates outstanding sensitivity. Notably, a visible color change can be detected within 3 s upon exposure to 1% H2 in air, with the color difference (ΔE) reaching up to 42 within 30 s and an accompanying transmittance change of 53%. Furthermore, the sensor exhibits stable and reliable cyclic performance, maintaining consistent responsiveness with no observable degradation (<5%) after 500 operational cycles. This innovative approach to gasochromic hydrogen sensing not only provides rapid and reliable leak detection but also ensures long-term stability and repeatability, making it a promising candidate for applications requiring high-sensitivity hydrogen monitoring.