Use of Palladium-Modified Polyaniline Electrode as a Sensitive Element of Fire Sensor

Abstract

Results of the development of a method for immobilizing nanosized palladium into an electrochemically synthesized polyaniline (PAn) electrically conductive porous matrix to create a sensitive element of an ignition sensor are presented. Two methods of manufacturing a sensitive element in the form of an electrode are investigated. The first method consists in the coprecipitation of polyaniline and palladium on a graphitized butyl rubber substrate in a mode of cycling of potential. It was shown that this method can be used to obtain a volume-porous electrode in which palladium nanoparticles are embedded in a polyaniline matrix. The second method involves the deposition of palladium on a polyaniline film formed on graphitized butyl rubber. It was shown that micron-sized island palladium conglomerates on the surface of a polyaniline film can be obtained by this method. The conclusions made are confirmed by physical research methods and the results of scanning electron microscopy. Investigations of the electrocatalytic properties of the electrode in the sensor model showed that with a change in the H2 concentration formed upon ignition, occurs change in the hydrogen concentration on the surface of metal-catalyst (Pd) and a linear change in the current of electrochemical reaction. Comparison of a composite volume-porous polyaniline electrode with embedded palladium showed its superior efficiency compared to a compact palladium electrode and an electrode in which palladium is deposited on the surface of a polyaniline film. The possibility of using an electrochemical detector based on polyaniline with immobilized palladium nanoparticles for a gas amperometric sensor of low hydrogen concentrations and a fire hazard detector is shown.