Constructing Fast Sensing‐Monitoring System via Spillover‐Free Hydrogen Reaction Path

ABSTRACT Hydrogen (H 2 ) leakage monitoring is paramount for the safety of hydrogen fuel cells. However, traditional metal‐sensitized oxide semiconductor sensors often suffer from sluggish response caused by the limited hydrogen spillover kinetics. Herein, we explore a spillover‐free hydrogen response strategy via constructing a disordered 3LiPdPt‐sensitized interface on ZnO supports (3LiPdPt/ZnO) for ultrafast and low‐concentration H 2 detection. We find the introduction of Li + can collapse the regular PdPt interface and induce stable amorphization even at high temperature. The resultant 3LiPdPt/ZnO sensor can achieve ultrafast response (<4 s) to 3–200 ppm H 2 , superior hydrogen response (13–50 ppm of H 2 ) and excellent long‐term stability. In‐situ experiments confirm that the disordered 3LiPdPt interface can bypass the hydrogen spillover limitation to realize a direct reaction between activated hydrogen and oxygen species. This path fundamentally eliminates the reliance on long‐range hydrogen diffusion and thus improves the sensing response speed reactive. Moreover, we demonstrate an autonomous monitoring system by equipping the sensors on fuel cell electric vehicle devices for dual‐mode (continuous/intermittent) H 2 leakage assessment. Therefore, our proposed strategy reveals a fundamental understanding of the hydrogen sensing mechanism and may create a new path for highly effective H 2 detection.