Production of positive ions during the catalytic oxidation of organic vapors on hot platinum

Abstract

A hot platinum surface will produce positive ions when exposed to organic vapors mixed in atmospheric air. The magnitude of the ionic response for alkanes and linear alcohols increases with the length of molecule and shows a double peak in the temperature variation (750 and 950/sup 0/C). However, the catalytic burning of ketones tends to produce more positive ions and shows higher currents for the smaller molecules. This decrease with increasing molecular weight approaches the value for the alkanes for large molecules. The ketones generally peak at 950/sup 0/C except for acetone, which peaks at 1050/sup 0/C. They conclude that the positive ions are correlated with the production of soot particles as they and the radicals involved in their formation would be capable of injecting electrons into the platinum metal.