Oxygen vacancies engineering and palladium quantum dots sensitized WO3 nanosheet for highly efficiently H2 detection

• We anchored palladium quantum dots on WO 3 nanosheets with surface oxygen vacancies . • Pd-WO 3 /WO x has excellent response to H 2 , excellent selectivity and good linearity. • Surface oxygen vacancies enhance H 2 adsorption via the d-band centre of the metal. Palladium is widely used in hydrogen sensing due to its excellent catalytic dissociation of hydrogen. However, the size, dispersion and density of palladium particles affect its role in enhancing gas-sensitive properties. In this work, we use a simple and effective method to anchor Pd quantum dots with the help of surface oxygen vacancies. The sensing results show that the response value (S = R a /R g ) of the material loaded with Pd quantum dots on surface oxygen vacancies (Pd-WO 3 /WO x ) for 50 ppm hydrogen at 160℃ is 13.37. Moreover, the Pd-WO 3 /WO x material exhibits excellent selectivity and good linearity over the test range. Furthermore, experimental results and DFT calculations reveal that surface oxygen vacancies can shift the d-band center of metallic Pd upward, which enhances the adsorption of hydrogen by Pd. This study provides new ideas for designing high-performance precious metal-loaded metal oxide semiconductor hydrogen sensors.