Pt Nanostructures Fabricated by Local Hydrothermal Synthesis for Low-Power Catalytic-Combustion Hydrogen Sensors

Hollow, microrod-like Pt nanostructures are locally synthesized on a small, suspended microheater platform (9 μm × 110 μm) as the catalytic layer of a low-power hydrogen (H2) catalytic combustion sensor. The Pt nanostructures are synthesized via two successive Joule heating-assisted chemical reactions. During operation, H2 locally combusts on the surface of the Pt nanostructures and transfers heat to the microheater, which in turn changes its resistance. Because of the highly localized Pt nanostructures and the suspended microheater, the sensor exhibits high sensitivity (ΔR/R0 ∼ 0.46% per percent of H2), fast response and recovery speeds (<12 s), and low-power consumption (4 mW).