Room-temperature H2 gasochromic behaviors of highly sensitive hexagonal phase WO3/Pt nanorods for eye-readable hydrogen leakage detection

Developing reliable and cost-effective optical hydrogen sensors detecting hydrogen leakage at room temperature is of paramount importance. It requires that hydrogen sensors show a rapid and significant color change in low concentration H 2 /air mixtures, which remains challenging. Herein, we demonstrate an eye-readable hydrogen sensor based on Pt decorated hexagonal WO 3 (W 0 /300/Pt). It is evidenced W 0 /300/Pt exhibits excellent gasochromic properties, with reflectivity differences of 78% and 73% and fast coloring times of 3.10   s and 2.64   s in 10% H₂/Ar and 10% H₂/air. Moreover, W 0 /300/Pt shows an obvious color change from light gray to dark blue finally with ΔE value of 71, and exhibits a detect limitation less than 0.1% H 2 in 1   s. The gasochromic mechanism related to crystalline phase structure was unveiled via in situ characterization techniques. This study also presents novel evidence that bolsters the “localized water molecules” model and provides theoretical insights for the advancement of highly sensitive WO 3 gasochromic materials.