Decorating Pd–Au Nanodots Around Porous In₂O₃ Nanocubes for Tolerant H₂ Sensing Against Switching Response and H₂S Poisoning

Abstract With the recently‐booming hydrogen (H₂) economy by green H₂ as the energy carriers and the newly‐emerged exhaled diagnosis by human organ‐metabolized H₂ as a biomarker, H₂ sensing is simultaneously required with fast response, low detection limit, and tolerant stability against humidity, switching, and poisoning. Here, reliable H₂ sensing has been developed by utilizing indium oxide nanocubes decorated with palladium and gold nanodots (Pd–Au NDs/In₂O₃ NCBs), which have been synthesized by combined hydrothermal reaction, annealing, and chemical bath deposition. As‐prepared Pd–Au NDs/In₂O₃ NCBs are observed with surface‐enriched NDs and nanopores. Beneficially, Pd–Au NDs/In₂O₃ NCBs show 300 ppb‐low detection limit, 5 s‐fast response to 500 ppm H₂, 75%RH‐high humidity tolerance, and 56 days‐long stability at 280 °C. Further, Pd–Au NDs/In₂O₃ NCBs show excellent stability against switching sensing response, and are tolerant to H₂S poisoning even being exposed to 10 ppm H₂S at 280 °C. Such excellent H₂ sensing may be attributed to the synergistic effect of the boosted Pd–Au NDs’ spillover effect and interfacial electron transfer, increased adsorption sites over the porous NCBs’ surface, and utilized Pd NDs’ affinity with H₂ and H₂S. Practically, Pd–Au NDs/In₂O₃ NCBs are integrated into the H₂ sensing device, which can reliably communicate with a smartphone.