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 WO 3 nanoplates as the sensing layer. At an optimum operating temperature of 200 °C, the hydrogen gas sensing capabilities of WO 3 and Pd-WO 3 composite sensors were investigated. The findings indicate that in contrast to the WO 3 sensor, the Pd-WO 3 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-WO 3 composite. The improved sensing performance of Pd-WO 3 composite sensors was explained from the perspectives of the Schottky junction formed between Pd nanoparticles and WO 3, the catalytic effect of metal Pd nanoparticles, and gas adsorption–desorption. This article confirms that Pd-modified WO 3 nanoplates are good candidates for efficient hydrogen gas sensing.