Palladium Nanoparticle-Based Catalytic Thermopiles for ppb-Level, Subsecond Detection of Acetylene Gas

Highly sensitive and rapid detection of trace acetylene (C₂H₂) gas is crucial for industrial safety but challenging for existing sensors. Herein, we present a catalytic thermopile-based C₂H₂ sensor, combining the lowest detection limit and fastest response time/recovery time among reported C₂H₂ sensors. Facilitated by Pd NPs@Al₂O₃ (∼3.5 nm in diameter) decorated on the specially engineered differential thermopiles, the sensors can detect the C₂H₂ concentration down to 5 ppb. The sensors also exhibit the fastest response/recovery time of 0.34/0.40s. The structural design allows a power consumption of only 27.2 mW at 340 °C and a temperature variation of just ∼1.2%, surpassing reported thermopile sensors. Combining the neuroevolution potential (NEP) and multiphysics modeling, we reveal the mechanism of Pd NP-catalyzed cascade bond-breaking and exothermic reaction of C₂H₂ molecules in oxygen from atomic-scale and energy perspective. This study highlights the potential of noble nanoparticle-based catalytic thermopiles for high-performance C₂H₂ detection in various industrial applications.