Catalytic-electronic coupling in Pd-decorated V2O5 nanoflowers enables low-temperature and low-power hydrogen sensing

Pd-decorated V 2 O 5 nanoflowers enable enhanced H2 response and detectable room-temperature sensing. • DRIFTS and DFT reveal catalytic-electronic coupling that promotes H2 dissociation, spillover, and charge transfer. • MEMS-integrated sensors achieve ultralow power consumption of 7.2 mW for portable H2 safety detection. Reliable hydrogen detection under high concentrations and low power consumption is crucial for ensuring safety in industrial environments. Here, we report Pd-decorated V 2 O 5 nanoflowers synthesized via a hydrothermal-impregnation route that achieve a high response of 13.43 to 2000 ppm H 2 at 75 °C—nearly six times that of pristine V 2 O 5 (2.32 at 200 °C)—along with excellent repeatability, selectivity, humidity tolerance, and long-term stability. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) measurements reveal the formation of Pd H and V 4+  = O species even at room temperature and density-functional-theory (DFT) calculations indicate enhanced charge transfer and reduced adsorption energy at the Pd/V 2 O 5 interface. These findings confirm a strong catalytic-electronic coupling effect, in which Pd catalyzes hydrogen dissociation and spillover, while interfacial electron redistribution and vacancy-mediated activation dramatically lower the reaction barrier. This synergistic coupling enables sensitive hydrogen sensing at significantly reduced temperatures. Integration of the Pd/V 2 O 5 layer into a Micro-Electro-Mechanical System (MEMS) platform yields an ultralow power consumption of 7.2 mW, demonstrating promising potential for miniaturized, energy-efficient hydrogen-sensing technologies.