Low-cost fabrication of rapid response gasochromic hydrogen sensor based on 3D hierarchical structured hexagonal WO3

Developing optical hydrogen sensors with fast response, high contrast, and low cost presents particular challenges. In this research, we synthesized Pd nanoparticle-doped hexagonal WO 3 nanoflowers using hydrothermal and photochemical deposition methods. 0.50 at% Pd-WO 3 samples exhibited excellent response speed (29 s) and contrast (color difference value is 6.08) for 1 % H 2 at room temperature. Considering the applicability and versatility of the sensor, we also simulated harsh outdoor environmental conditions to conduct environmental stability tests on the samples. The material demonstrated exceptional cycling stability, high selectivity, and environmental stability as well. Compared to other crystal phases of WO 3 , the hexagonal WO 3 crystal structure provides a unique tunnel structure that enhances charge transfer capabilities. The synthesized nanoflower-shaped WO 3 with a hierarchical structure offers a significant specific surface area for reactions. The photodeposition of Pd nanoparticles resulted in a more uniform doping, and the synergistic effects of the three components collectively enhanced the material's gasochromic performance. This work presents a low-cost and efficient hydrogen-sensitive material that better meets the demands of practical industrial applications.