Metalloporphyrins-functionalized carbon nanotube networked films for room-temperature VOCs sensing applications

AbstractNetworked films of carbon nanotubes (CNTs) have been grown by Chemical Vapor Deposition (CVD) technology onto cost-effective alumina substrate, coated by Cobalt nanocatalyst for growing the CNTs. The sidewalls of the CNTs films have been functionalized by spray-coating with two different metalloporphyrins (MPP), consisting of a Tetraphenylporphyrin coordinated by a central metal of zinc (Zn-TPP) and manganese (Mn-TPP). The surface-modification of the CNTs with layers of Zn-TPP and Mn-TPP provides enhanced sensitivity and broad selectivity to volatile organic compounds (VOCs). The chemical interactions of these MPP-modified CNTs films with different tested VOCs (alcohols, esters, aromatics, ketones) have been investigated using the miniaturized two-pole chemiresistors technique. The sensor response in terms of p-type electrical conductance in the MPP-modified CNTs-chemiresistors exhibits a good sensing performance, at room temperature. The findings show a VOC adsorption occuring by sensing characteristics of response-concentration relationships as a combined Langmuir-Henry behaviou