Semiconducting metal oxides and metal catalysts have been widely used for gas sensors with high precision and reliability. In this study, we report a Pd-WO₃ based chemiresistive sensor that can detect hydrogen at the ppm level at room temperature with a remarkably high response and selectivity. The colloidal solutions with Pd and WO₃ nanoparticles were spray-deposited with controlled charge states of the droplets. The self-assembly of Pd nanoparticles (positive surface charge) and WO₃ nanoparticles (negative surface charge) was reinforced with the positively charged droplets, producing Pd-WO₃ nanoparticles with 1.68 times higher surface coverage of Pd on WO₃ and a higher uniformity compared to those produced with neutral droplets. The optimized Pd-WO₃ sensor fabricated by the positively charged droplets exhibits a 160 times higher response and 3.51 times faster response for 100 ppm of hydrogen than sensors fabricated by the neutral droplets, detecting hydrogen concentrations as low as 1 ppm with excellent cyclic stability, selectivity, and reproducibility.

半导体金属氧化物和金属催化剂已广泛用于高精度和高可靠性的气体传感器。在这项研究中，我们报告了一种基于 Pd-WO ₃的化学电阻传感器，该传感器可以在室温下以非常高的响应和选择性检测 ppm 水平的氢。具有 Pd 和 WO ₃纳米颗粒的胶体溶液在液滴的受控电荷状态下进行喷雾沉积。带正电荷的液滴增强了Pd 纳米粒子（表面正电荷）和 WO _{3纳米粒子（表面负电荷）的自组装，产生的 Pd-WO 3纳米粒子在 WO 3}上的表面覆盖率是 Pd 表面覆盖率的 1.68 倍与中性液滴相比，均匀性更高。由带正电液滴制造的优化 Pd-WO ₃传感器对 100 ppm 氢气的响应比中性液滴制造的传感器高 160 倍，响应速度快 3.51 倍，检测氢浓度低至 1 ppm 并具有出色的循环稳定性，选择性和重现性。