Pd-Doped WO3 Nanoplates for Hydrogen Sensing: Experimental Studies and Density Functional Theory Investigations

In this article, a hydrogen sensor with excellent performance was synthesized using the hydrothermal method, with Pd-modified WO₃ nanoplates as the sensing layer. At an optimum operating temperature of 200 °C, the hydrogen gas sensing capabilities of WO₃ and Pd-WO₃ composite sensors were investigated. The findings indicate that in contrast to the WO₃ sensor, the Pd-WO₃ composite sensor exhibits superior hydrogen sensing performance, showcasing remarkable selectivity, reliable repeatability, sustained long-term stability, and quick response and recovery (8 s/10 s@100 ppm). The first-principles density functional theory was used to explain the sensing mechanism of the Pd-WO₃ composite. The improved sensing performance of Pd-WO₃ composite sensors was explained from the perspectives of the Schottky junction formed between Pd nanoparticles and WO₃, the catalytic effect of metal Pd nanoparticles, and gas adsorption–desorption. This article confirms that Pd-modified WO₃ nanoplates are good candidates for efficient hydrogen gas sensing.