Highly Sensitive Detection of Hydrogen Gas Using Nanoporous Composites of Halloysite Nanotubes and Palladium

Hydrogen (H 2 ) detectors are important tools to ensure the safety in H 2 production/storage/transportation/use and also monitor many H 2 -related physiochemical processes in industrial or medical practices. Ideal H 2 detectors should not only have high detection performance (e.g., high sensitivity and selectivity) but also possess low power-consumption, high compactness, simple fabrication using low-cost materials, and ease of instrumentation that can be easily handled and operated. In this work, nanoporous composites by simply reducing palladium (Pd) precursors to the surface of halloysite nanotubes (HNTs) were developed and optimized for the development of a resistive H 2 detector. The detector was prepared by depositing solution droplets of Pd/HNT with an optimal mass concentration on an interdigitated microelectrode surface of 1 cm × 1 cm and then drying it at 65 °C. The developed H 2 detector exhibited reliable H 2 detection, achieving low limit H 2 detections of 27 ppb and <10 ppm in both N 2 and air, respectively. It also presented high selectivity, differencing H 2 from other interfering gases such as CO 2 and CH 4, and demonstrated stability in its response from room temperature to 50 °C. We attribute the characteristics of the detector performance to the nature of Pd/HNT composites (large surface, high porosity, specific reaction of Pd to H 2, etc.). Given its high detection performance, simple resistance read-out, and ease of fabrication, it is believed that the developed detector will have broad applications in the H 2 energy industry and many other H 2 -related industrial and medical procedures.