High-Performance Hydrogen Sensors for ppb-Level Detection at Room Temperature Using Pd Nanoparticle-Coated Si Nanoforest

The development of hydrogen (H2) sensors with parts-per-billion (ppb)-level detection limits, high sensitivity, and room-temperature operation is of paramount importance for ensuring industrial safety and advancing H2-based energy technologies. While numerous studies have reported ppb-level detection, challenges such as room-temperature operation, selectivity, and integration remain significant obstacles. Here, we report a high-performance H2 sensor capable of detecting ppb-level H2 at room temperature with exceptional sensitivity and reliability. The sensor is based on palladium nanoparticles (Pd NPs)-functionalized silicon (Si) nanoforest structures, which offer a high surface-to-volume ratio (H-SVR), facilitating enhanced gas adsorption and interaction. The optimized sensor exhibits a remarkable response of 1685% to 1% H2 at room temperature, along with an ultralow detection limit of 50 ppb. In addition, it demonstrates excellent batch-to-batch reproducibility, strong selectivity, and adaptability to high-humidity environments, highlighting its outstanding H2 sensing performance. The superior H2 sensing performance is attributed to the synergistic effects of Pd-catalyzed H2 dissociation, enhanced adsorption due to the high surface area of the Si nanoforest, and charge modulation at the Pd/Si Schottky junction. The developed sensor holds significant potential for advancing next-generation H2 sensing platforms, which are critical for industrial safety, environmental monitoring, and H2 economy applications.