Enhanced H2 gas sensing properties by Pd-loaded urchin-like W18O49 hierarchical nanostructures

Noble metal-semiconductor gas sensors have attached much attention owing to its high sensitivity and excellent selectivity. In this work, non-stoichiometry urchin-like Pd-W18O49 nanostructures are developed for gas sensing applications. Such hierarchical nanostructures were synthesized by two-step approach including a hydrothermal reaction and a subsequent incipient wetness impregnation process. The high sensitivity and excellent selectivity distinguish this sensor from the traditional Pd-WO3 sensor. An insight into the outstanding performance of Pd-W18O49 is provided by contrasting the sensing characteristics of W18O49 and Pd-WO3, which exhibit lower selectivity and response to hydrogen. By comparison, the observed response of Pd-W18O49 sensor is up to 1600-in 0.1 vol% hydrogen at a low working temperature of 100 degrees C. The excellent and enhanced H-2 sensing performances of Pd-W18O49 sensor can be attributed to its novel hierarchical structure, abundant oxygen vacancies, and the catalytic activity of Pd nanoparticles. (C) 2018 Elsevier B.V. All rights reserved.