Abstract
In the current contribution, Pd@Pt core-shell nanocrystals-based resistivity-type sensor has been realized with the aim of implementing a fast-response hydrogen (H-2) sensor and investigating the effect of shell thickness on sensing properties. Pd Pt core-shell nano crystals as colloids were synthesized via a chemical route and were then carefully assembled on a SiO2/Si substrate using the self-assembly monolayer (SAM) technique. Three different Pd@Pt core-shell nanocrystals with varied Pt shell thicknesses were synthesized for the SAM process. The short diffusion length of Pd Pt due to the thin Pt shell layer and the monolayer-distribution of the Pd Pt core-shell preferentially accelerated the adsorption desorption of the H-2 molecules on the sensing interface, resulting in a very quick response to H-2 gas. At an optimum operating temperature of 150 degrees C, the sensor showed a fast-response time of 6 s, a maximum response of 3.6% to 1 vol.% gas concentration, and a broad detection range of 0.001-4 vol.% H-2 concentrations. The aforementioned outcomes of the as-fabricated sensor demonstrate the possibility of implementing an efficient H-2 sensor for safety applications. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.