Hydrogen Sensors Based on Flexible Carbon Nanotube-Palladium Composite Sheets Integrated with Ripstop Fabric

Abstract

This work describes the design and fabrication of free-standing carbon nanotube-palladium (CNT-Pd) composite sheets for hydrogen gas sensing. The CNT-Pd composites were made by electroplating palladium onto a solvent-densified and oxygen plasma-treated CNT sheet. The latter was prepared using high purity CNTs drawn from a dense, vertically aligned array grown by chemical vapor deposition on silicon substrates. The CNT-Pd sheets were characterized by energy-dispersive spectroscopy, scanning electron microscopy, and X-ray diffraction. The amount of palladium in the composite was 16.5 wt % as measured via thermogravimetric analysis. Thin strips of the CNT-Pd sheets were assembled as chemiresistor sensors and tested for hydrogen gas detection. The sensors demonstrated a limit of detection of 0.1 mol % and displayed signal reversibility without the need for oxygen removal or heat treatment. A decrease in signal reversibility was observed after multiple exposure cycles; however, redensification with ethanol significantly restored the original reversibility. The sensor showed the Freundlich adsorption isotherm behavior when exposed to hydrogen. The material's potential application toward a wearable, flexible sensor was demonstrated by integrating the chemiresistor onto a fabric material using hot-press processing and testing the composite for hydrogen sensitivity.

Graphene-Based Hydrogen Gas Sensors: A Review

“…An overview of the problem of hydrogen sensing has not long ago been reported by Chauhan and Bhattacharya [48]. However, even with this much research and review, there is still a need to summarize the applicability of graphene and its derivatives for hydrogen sensing, paying special attention to the semiconductor principle of operation; this is the main target of this work [49][50][51][52][53][54][55][56][57]. Graphene and its derivatives present diversified useful properties, such as susceptibility to the insertion of surface functional groups and metal clusters, steerable electric properties and morphology.…”

Recent trends in gas sensingviacarbon nanomaterials: outlook and challenges

“…177 Furthermore, together with CNTs, Pd is generally used due to its high catalytic activity towards H 2 gas. 84,178,179 In 2018, Xiao et al performed H 2 sensing on Pd nanoparticle (Pd NP)-decorated SWCNTs. 180 When H 2 is exposed to the Pd-decorated CNTs, it would interact in two Fig.…”

Carbon Nanotube Sheet-Synthesis and Applications

“…CNT use in different applications has kept growing since its first discovery in 1991 by Iijima [ 35 ]. Applications include fiber-reinforced material [ 36 ], water filtration, air filtration, energy storage [ 37 ], supercapacitors [ 38 ], textiles [ 39 ], structural health monitoring, and hydrogen sensors [ 40 ], to mention a few. The increasing integration of CNT material in various applications can be accelerated by doping CNT material with different elements of the periodic table to make it multifunctional.…”