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

Abstract With the recently‐booming hydrogen (H 2 ) economy by green H 2 as the energy carriers and the newly‐emerged exhaled diagnosis by human organ‐metabolized H 2 as a biomarker, H 2 sensing is simultaneously required with fast response, low detection limit, and tolerant stability against humidity, switching, and poisoning. Here, reliable H 2 sensing has been developed by utilizing indium oxide nanocubes decorated with palladium and gold nanodots (Pd–Au NDs/In 2 O 3 NCBs), which have been synthesized by combined hydrothermal reaction, annealing, and chemical bath deposition. As‐prepared Pd–Au NDs/In 2 O 3 NCBs are observed with surface‐enriched NDs and nanopores. Beneficially, Pd–Au NDs/In 2 O 3 NCBs show 300 ppb‐low detection limit, 5 s‐fast response to 500 ppm H 2 , 75%RH‐high humidity tolerance, and 56 days‐long stability at 280 °C. Further, Pd–Au NDs/In 2 O 3 NCBs show excellent stability against switching sensing response, and are tolerant to H 2 S poisoning even being exposed to 10 ppm H 2 S at 280 °C. Such excellent H 2 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 H 2 and H 2 S. Practically, Pd–Au NDs/In 2 O 3 NCBs are integrated into the H 2 sensing device, which can reliably communicate with a smartphone.