The safe application of H2 gas requires a high-performance H2 gas sensing system. An attractive H2 gas sensor for industrial application which has H2 gas selectivity, high sensitivity, high response, high durability, small size, and low cost has not been developed yet. Durability is one of the most important problems in H2 gas sensors using Pd. This study focused on electric resistivity changes in metallic Pd with hydrogen gas absorption. Nanostructured palladium (NSPd) films for a hydrogen gas sensing material were fabricated by a dealloying method using dilute citric acid. Fabricated NSPd films exhibited a nanoscaled network structure or aggregated particle structure, a linear electric resistance change with hydrogen gas concentration, and high sensitivity compared to flat pure Pd films. Therefore, NSPd film is useful for hydrogen gas sensing applications and has both high sensitivity and low usage of the noble metal. Furthermore, we also revealed a degradation mechanism of pure Pd film due to repeated H2 gas exposure, and this phenomenon did not appear in the NSPd film. NSPd also showed a higher durability with repeated H2 gas exposure compared to pure Pd film. We concluded that NSPd is suitable for use as a practical H2 gas sensor due to its cost effectiveness and high sensing ability.

中文翻译：

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稀柠檬酸脱合金制备用于氢气传感的纳米结构钯薄膜的开发与评价

H2 气体的安全应用需要高性能的 H2 气体传感系统。尚未开发出具有氢气选择性、高灵敏度、高响应、高耐用性、小尺寸和低成本的工业应用的有吸引力的氢气传感器。耐久性是使用 Pd 的 H2 气体传感器中最重要的问题之一。本研究侧重于氢气吸收时金属 Pd 的电阻率变化。通过使用稀柠檬酸的脱合金方法制造了用于氢气传感材料的纳米结构钯（NSPd）薄膜。与平坦的纯 Pd 薄膜相比，制造的 NSPd 薄膜表现出纳米级网络结构或聚集颗粒结构、电阻随氢气浓度的线性变化以及高灵敏度。所以，NSPd 薄膜可用于氢气传感应用，具有高灵敏度和低贵金属使用率。此外，我们还揭示了由于反复暴露于 H2 气体而导致纯 Pd 薄膜的降解机制，而这种现象在 NSPd 薄膜中没有出现。与纯 Pd 薄膜相比，NSPd 在反复接触 H2 气体时也表现出更高的耐久性。我们得出结论，由于 NSPd 的成本效益和高传感能力，它适合用作实用的 H2 气体传感器。