Temperature-dependent H2 gas-sensing properties of fabricated Pd nanowires using highly oriented pyrolytic graphite

Abstract

Horizontal palladium (Pd) nanowires and Pd nanoparticles were successfully fabricated directly on highly oriented pyrolytic graphite depending on the electrodeposition time using palladium nitrate [Pd(NO2)(3)] solution at room temperature, and the temperature-dependent hydrogen (H-2) sensing properties of these structures were investigated in the concentration range of 50-5000 ppm. Pd nanowires and Pd nanoparticles were fabricated on a graphite surface by applying triple-pulsed potential with varying the electrodeposition time from 400 to 600 s. The fabricated Pd nanowires were characterized by scanning electron microscopy and energy-dispersive x-ray spectroscopy. It was found that the nanowire arrays were continuous, parallel to each other and ordered after an electrodeposition time of 600 s. The diameters of the Pd nanowires and Pd nanoparticles are observed in the range of 70-180 nm. The H-2 sensing properties of these structures were determined with variation in resistance measurements. It was observed that the limit of detection is lower than 50 ppm H-2, the sensor response was approximately 2% for 1000 ppm H-2 at room temperature, and the sensor response was decreased with increasing temperature. (C) 2010 American Institute of Physics. [doi:10.1063/1.3481430]