Metal dispersions on zirconium phosphates. 1. Hydrogen reduction of copper-exchanged .alpha.-zirconium phosphate
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The reduction of Cu(II) by hydrogen in copper-exchanged α-zirconium phosphate, ZrCu(PO4)2, was found to proceed in two stages. Below about 150 torr the product was ZrCuH(PO4)2, which in turn reacted further with hydrogen above H2pressures of 150 torr to yield copper metal and λ-zirconium phosphate. The rates of both reactions were found to conform to an Elovich-type equation and to be strongly pressure dependent. These results were interpreted in terms of the sorption and diffusion of H2to the metal as the rate-controlling step. Activation energies were low (7.1 and 5.7 kcal/mol) for both stages of the reduction, as expected for a diffusion-controlled reaction. The concept of active-site generation is introduced to account for the observed induction period. © 1982 American Chemical Society.
author list (cited authors)
Clearfield, A., Thakur, D. S., & Cheung, H.