Two‐dimensional Aluminum Oxide Nanosheets Decorated with Palladium Oxide Nanodots for Highly Stable and Selective Hydrogen Sensing

Hydrogen (H2 ) sensing materials such as semiconductor metal oxides may suffer from poor long-term stability against humidity and unsatisfactory selectivity against other interfering gases. To address the above issues, highly stable and selective H2 sensing built with palladium oxide nanodots decorating aluminum oxide nanosheets (PdO NDs//Al2 O3 NSs) has been achieved via combined template synthesis, photochemical deposition, and oxidation. Typically, the PdO NDs//Al2 O3 NSs are observed with thin NSs (≈17 nm thick) decorated with nanodots (≈3.3 nm in diameter). Beneficially, the sensor prototypes built with PdO NDs//Al2 O3 NSs show excellent long-term stability for 278 days, high selectivity against interfering gases, and outstanding stability against humidity at 300 °C. Remarkably, the sensor prototypes enable detection of a wide-range of 20 ppm - 6 V/V% H2 , and the response and recovery times are ≈5 and 16 s to 1 V/V% H2 , respectively. Theoretically, the heterojunctions of PdO NDs-Al2 O3 NSs with a large specific surface ratio and Al2 O3 NSs as the support exhibit excellent stability and selective H2 sensing. Practically, a sensing device integrated with the PdO NDs//Al2 O3 NSs sensor prototype is simulated for detecting H2 with reliable sensing response.