Balancing Pd–H Interactions: Thiolate‐Protected Palladium Nanoclusters for Robust and Rapid Hydrogen Gas Sensing

Abstract The transition toward hydrogen gas (H 2 ) as an eco‐friendly and renewable energy source necessitates advanced safety technologies, particularly robust sensors for H 2 leak detection and concentration monitoring. Although palladium (Pd)‐based materials are preferred for their strong H 2 affinity, intense palladium–hydrogen (Pd–H) interactions lead to phase transitions to palladium hydride (PdH x ), compromising sensors’ durability and detection speeds after multiple uses. In response, this study introduces a high‐performance H 2 sensor designed from thiolate‐protected Pd nanoclusters (Pd 8 SR 16 ), which leverages the synergistic effect between the metal and protective ligands to form an intermediate palladium–hydrogen–sulfur (Pd–H–S) state during H 2 adsorption. Striking a balance, it preserves Pd–H binding affinity while preventing excessive interaction, thus lowering the energy required for H 2 desorption. The dynamic adsorption‐dissociation‐recombination‐desorption process is efficiently and highly reversible with Pd 8 SR 16 , ensuring robust and rapid H 2 sensing at parts per million (ppm). The Pd 8 SR 16 ‐based sensor demonstrates exceptional stability (50 cycles; 0.11% standard deviation in response), prompt response/recovery (t 90 = 0.95 s/6 s), low limit of detection (LoD, 1 ppm), and ambient temperature operability, ranking it among the most sensitive Pd‐based H 2 sensors. Furthermore, a multifunctional prototype demonstrates the practicality of real‐world gas sensing using ligand‐protected metal nanoclusters.