Palladium/Palladium Oxide Nanosheet Heterostructures by Partial Reduction for Sub-Parts per Million Hydrogen Detection at Room Temperature

To address the energy crisis and mitigate greenhouse gas emissions, substantial investments are advancing hydrogen (H2) technologies. Reliable, efficient room-temperature H2 sensors are critical for ensuring safe H2 production and utilization. Here, we report a palladium/palladium oxide (Pd/PdO) nanosheet composite capable of detecting H2 concentrations as low as 0.5 ppm at room temperature. The sensor exhibits exceptional stability, maintaining this detection limit after four months under ambient conditions. The superior H2 sensing performance stems from two key features: (1) the ultrathin nanosheet morphology, which offers abundant reactive sites, and (2) Pd nanoregions that enhance chemical and electronic sensitization. Together, these attributes synergistically elevate room-temperature H2 detection. This work demonstrates a promising strategy for advancing H2 sensor performance, supporting the transition to a hydrogen-based economy.