Hydrogen sensing properties of Pt/Pd bimetal decorated on highly hydrophobic Si nanowires

This paper describes the synthesis of Pt/Pd bimetal decorated highly hydrophobic rough silicon nanowires (Si NWs) by using a facile metal assisted chemical etching and pulse laser deposition (PLD) process. In addition, the potential of the Si NWs as a new hydrogen (H-2) detection matrix was investigated. The Pt/Pd bimetal was coated as a discrete ultra thin film manner in a semi-dense configuration over the basal podium and along the length of vertical-standing and semi-densely distributed rough Si NW clusters. The resulting structure showed significant advantages in H-2 sensing performances such as a large detection range of 1-40,000 ppm, high response magnitude of nearly 5.02%, and fast response-recovery time of 7/7 s to 10,000 ppm (1 vol%) hydrogen concentration at an optimum operating temperature of 75 degrees C. The observed characteristics of fast response recovery time could relate to the enhanced hydrogen-induced changes in the work function of the Pt/Pd bimetal decorated Si NWs (Pt/Pd-Si NWs), which were configured as an array matrix comprising of many nanowire clusters with variable distances between the two electrodes. Finally, the fabricated sensor showed excellent repeatability towards (1 vol %) hydrogen concentration. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.