Hydrogen (H₂) is a clean energy carrier of increasing importance; however, its safe handling and storage require reliable hydrogen sensing technologies. Palladium (Pd) is widely recognized as an effective material for hydrogen detection due to its strong affinity for H₂, yet Pd-based sensors commonly face performance trade-offs related to loading ratio and aggregation. In this work, a lattice-mismatch-assisted surface functionalization approach is employed to enable uniform growth of Pd nanoparticles on MXene surfaces. Uniformly distributed Pd nanoparticles are achieved at a modification level from 5% to 20%. Among the investigated compositions, the MXene functionalized with 10%Pd-based gas sensor exhibits the best sensing performance, demonstrating a 10-15 times higher response towards 100 ppm H₂ compared with pristine MXene. The developed hydrogen gas sensors operate at room temperature with low power consumption and show excellent sensitivity. This work paves a new way to develop highly MXene based gas sensors towards highly sensitive hydrogen detection.