The recent transition to H2-based energy storage demands for reliable H2 sensors that allow for easy, fast, and reliable detection of leaks. Conventional H2 detectors are based on the H2 probes of changes of physical properties induced by subsurface H-atoms to a material, such as electrical conductivity. Herein, we report on highly reactive gasochromic H2 detectors based on the adsorption of H2 on the material surface. We prepared supraparticles (SPs) containing different types of noble metal nanoparticles (NPs), silica NPs, and the dye resazurin by spray‑drying and tested their performance for H2 detection. The material undergoes a distinct color change due to the hydrogenation of the purple resazurin to pink resorufin and, finally, colorless hydroresorufin. The step-wise transition is fast and visible to the naked eye. To improve further the performance of the sensor, we tested the reactivity of SPs with different catalytically active NPs by means of in situ DRIFTS. We show that choice of the NP catalyst has a pronounced effect on the response of the H2 indicator. In addition, we demonstrate that the performance depends on the size of the NPs. These effects are attributed to the availability of reactive H‑atoms on the NP surface. Among the materials studied, Pt-containing SPs gave the best results for H2 detection.