Hydrogen gas sensor: self-heating based array of single suspended carbon nanowires decorated with palladium nanoparticles

Abstract

This study reports the development of a novel hydrogen gas sensor based on an array of single suspended carbon nanowires ( ~ 200 nm, length ~ 100 m) decorated with Pd nanoparticles (PdNPs) of various sizes for room temperature H2 gas sensing. These sensors provide high sensitivity, a wide sensing range (10 ppm − 5 %), and complete gas response recovery in 5 s with ultralow power consumption (30 W). Such performance is achieved using a novel suspended PdNP/carbon nanowire architecture, which offers enhanced mass transfer, high surface area to volume ratios, and good thermal insulation. This platform can be fabricated using simple batch microfabrication processes including carbon-MEMS and electrodeposition. The sensitivity and range of the sensor can be modulated by controlling Pd nanoparticle sizes (3 – 5 nm PdNPs: 3.2 % ppm-1/2, 10 − 1,000 ppm; 10 – 15 nm PdNPs: 0.32 % ppm-1/2, 700 ppm − 5 %). A wide sensing range is achieved by integrating nanowires with various sizes of PdNPs onto a chip. The electrical resistance of a suspended PdNP/carbon nanowire quickly and completely recovers its original state in a very short time via ultralow-power, Joule heat-based self-heating. This self-heating-based system achieves reliable, continuous, and long-term H2 detection.