HYDROGEN PEROXIDE VAPOUR SENSOR USING METAL PHTHALOCYANINE FUCTIONALIZED CARBON NANOTUBES

摘要

The present invention relates to the development of a process for functionalization of multi-walled carbon nanotubes by metal-phthalocyanines and their use as highly selective and sensitive sensor for detection of hydrogen peroxide in the vapour phase. The invention provides a process in which multiwall carbon nanotubes (CNT) are first functionalized using corona electrostatic discharge technique and then a composite consisting of these functionalized CNT"s and metal-Pc is prepared via non-covalent methods like blending technique (ultrasonification and magnetic stirring) resulting in the metal-Pc functionalized CNT"s. These metal-Pcs functionalized CNT"s have been used for detection of H2O2 vapours with very high selectivity and sensitivity. A combination of Cobalt-Pc and Copper-Pc thin film sensors has been found to show opposite conductivities to H2O2 vapours making this paired sensor as a highly reliable method to selectively identify the presence of H2O2 vapours unambiguously. Our developed sensors have resistivity in the kilo-ohm range with response and recovery times of few seconds. This technique for fabrication of sensors is simple, fast, low cost and does not require any expensive or specialized equipment. The thin films can be formed on almost any substrate including glass, plastic and irregularly shaped substrates and is very cost effective. The sensors work at room temperature, little interference from water vapours, show resistivity in the kilo-ohm range making it easier for impedance matching with amplifying circuits and can be used in industrial and other real life applications. These properties make our sensors very attractive for commercial applications for detection of H2O2 vapours in industrial plants for paper and pulp industries, laundry detergents, environmental and health care areas etc. and in the detection of H2O2 based explosive devices.