Fingertip-chip sensor based on Pd nanocluster sensitized 3D NiO nanotube arrays for real-time, selective methane detection

The selective detection of methane (CH₄) at trace levels is essential for applications such as mining safety and natural gas leak detection. However, achieving high selectivity and sensitivity remains a significant challenge due to interference from gases like hydrogen sulfide (H₂S) and carbon monoxide (CO). In this study, we present a novel fingertip-chip sensor that combines palladium (Pd) nanoclusters with three-dimensional (3D) nickel oxide (NiO) nanotube arrays for highly selective and sensitive CH₄ detection. The 3D NiO structure offers a large surface area that enhances CH₄ adsorption, while the Pd nanoclusters serve as catalytic sites, improving the interaction between CH₄ molecules and the NiO surface. Fabricated via atomic layer deposition (ALD), the sensor demonstrates an ultra-low detection limit of 70 parts per billion (ppb) and exceptional selectivity, with a response ratio greater than 10 for CH₄ relative to common interferents such as H₂S and CO. Comprehensive evaluations of the sensor's sensitivity, stability, and performance under varying environmental conditions confirm its potential for real-time monitoring. Integrated into a wireless fingertip-chip system, the sensor enables seamless, remote CH₄ monitoring in dynamic and challenging environments, such as mining sites and natural gas pipelines. This work presents a scalable approach for next-generation safety gas sensors, enhancing both detection sensitivity and real-time applicability in industrial and environmental monitoring.