Pd Decoration with Synergistic High Oxygen Mobility Boosts Hydrogen Sensing Performance at Low Working Temperature on WO 3 Nanosheet.

Pd-based materials have received remarkable attention and exhibit excellent H 2 sensing performance due to their superior hydrogen storage and catalysis behavior. However, the synergistic effects originated from the decoration of Pd on a metal oxide support to boost the sensing performance are ambiguous, and the deep investigation of metal support interaction (MSI) on the H 2 sensing mechanism is still unclear. Here, the model material of Pd nanoparticle-decorated WO 3 nanosheet is synthesized, and individual fine structures can be achieved by treating it at different temperatures. Notably, the Pd-WO 3 -300 materials display superior H 2 sensing performance at a low working temperature (110 °C), with a superior sensing response ( R a / R g = 40.63 to 10 ppm), high sensing selectivity, and anti-interference ability. DFT calculations and detailed structural investigations confirm that the moderate MSI facilitates the generation of high mobility surface O 2 - (ad) species and a proper ratio of surface Pd 0 -Pd 2+ species, which can significantly boost the desorption of intermediate PdH x species at low temperatures and contribute to enhanced sensing performance. Our work illustrates the effect of MSI on sensing performance and provides insight into the design of advanced sensing materials.