A surface reaction occurs on a catalyst surface when the catalyst sample is heated up to a certain temperature in a reactive mixture. After the surface reaction occurs, a steady state is observed without energy supply because the heat produced by the surface reaction is balanced with the heat loss caused by convection, conduction and radiation. The heat release of the surface reaction can be evaluated by the surface temperature of the catalyst sample at the steady state.
This paper treats the effects of the equivalence ratio (ER) and the dilution ratio (DR) of the reactive mixture on the surface reaction. Hydrogen and oxygen are used as reactive mixture and nitrogen as inert gas. The height, width and length of the combustion chamber are 76mm, 140mm and 140mm, respectively. A spherical Pt catalyst sample of 1.5mm in diameter is sustained in the chamber with two wires of 0.1 mm in diameter. The chamber is filled with a hydrogen-oxygen-nitrogen mixture at the atmospheric pressure and the room temperature. The surface temperature is measured with a thermocouple. As the results, the heat produced by the surface reaction decreases with increasing dilution ratio, and hydrogen is adsorbed more easily compared with oxygen.
