CATALYTIC DECOMPOSITION OF HYDROGEN PEROXIDE BY METALS AND ALLOYS OF PLATINUM GROUP

The catalytic decomposition of dilute aqueous solutions of hydrogen peroxide has been studied on a number of Group VIII metals and binary alloys, including palladium-gold. The kinetics were measured at 27 ° as a function of catalyst composition and pH of the solution. In neutral solution, the activity of the individual metals of Group VIII3 was generally greater than those of Group VIII2, the order of specific activity (per unit surface area) decreasing in the sequence Pt > Os > Ir > Pd > Ru > Rh. Alloys of PtPd, PtRu and PtRh showed activities intermediate between those of the constituent metals. Alloys of PtIr and PdAu exhibited maximum activities at intermediate alloy compositions. The kinetics depended strongly on the pH of the solutions, the rate rising to a sharp maximum at pH values of 10-11, in accordance with the radical-chain mechanism for the decomposition. © 1969.