STRUCTURE OF THE CATALYTIC SITE OF A SILICA-SUPPORTED COPPER, MANGANESE CATALYST

The structure and the oxidation state of a copper-manganese catalyst h as been clarified by means of XAFS at three stages: fresh (as-prepared ), oxidized and reduced. Copper and manganese take highly dispersed st ructure in fresh stage. By oxidizing it, Cu-Mn, Cu...Cu and Mn...Mn in teractions are formed, but there was little indication of Cu-Cu bond. Metallic copper, copper(I) oxide and manganese(II) oxide are formed in reduced stage. Through the process the valency of copper changes II-- >II and I-->I and 0 but that of manganese was kept at II. The high cat alytic activity of this catalyst can be ascribed to copper species act ivated by the Mn-Cu interaction but the mechanism is different from th at was proposed for Hopcalite.