Adsorption of Hydrogen on Copper-Magnesia Catalysts

Abstract

Abstract (1) The adsorption of hydrogen on a copper catalyst containing 1% magnesia sintered at various temperatures has been investigated at 100° and 160°C, and compared with that on copper alone. The addition of magnesia increases markedly both the surface area and the rate of adsorption. The latter increase, however, is far beyond the increase in surface area. (2) The hydrogen adsorption per unit area of the copper magnesia catalyst is less than that on pure copper, and decreases with increasing heat treatment. The adsorption of hydrogen on magnesia powder is immeasurably small. The heat curves on differently heated catalysts do not agree with each other, but approximately do so if the effective area for hydrogen adsorption is taken into consideration. The adsorption heat for a low coverage is certainly greater on the magnesia added copper than on copper alone. (3) By aid of the electron diffraction study, it is concluded that the magnesia in the catalysts exists on the surface and forms microcrystal particles. Presumably, copper in the magnesia added catalyst is modified by the oxygen of the magnesia and irregular defects are formed on the surface in the presence of magnesia.