Rapid and Selective Detection of Trace Hydrogen by Mesoporous SnO₂ Anchored with Au–Pd Dual-Atom Sensitizers

Due to weak interactions between hydrogen molecules and sensing materials as well as slow H₂ oxidation kinetics, traditional semiconductor metal oxides (SMOs) have limited capability for selective and rapid hydrogen sensing. We propose an innovative strategy to enhance gas-sensing performance by modifying SMOs with atomically dispersed dual noble-metal sensitizers, differing from conventional single-atom or nanoparticle sensitizers. This sensor shows fast response time (1 s), strong resistance to CO, NO, H₂S, and SO₂ interference, and an ultralow detection limit (70 ppb) toward hydrogen, surpassing single noble-metal modified hydrogen sensors. The excellent sensing performance can be attributed to the synergistic sensitization of atomically dispersed Au/Pd dual catalysts with complementary gas activation properties. The hand-held hydrogen detector, featuring a fast response (<1 s), demonstrates robust early warning capability for H₂ leakage. This work introduces an atomically dispersed dual noble-metal sensitization strategy for superior hydrogen sensing, paving the way for hydrogen safety.