Electrodeposition of Cu+PdO and (Cu-Pd)+PdO Composites

The codeposition of PdO particles with a Cu matrix has been investigated with the aim of extending the composite deposition procedure to the preparation of materials potentially capable of catalyzing the low temperature combustion of methane. Cu + PdO composites with a low dispersed phase content were obtained from either basic pyrophosphate or acid sulfate baths. Codeposition of PdO particles with a Cu-Pd alloy matrix was effectively achieved by electrolyzing suspensions of PdO in solutions containing both Cu 2+ and Pd 2+ ions, with large [Cu 2+ ]/[Pd 2+ ] ratios. (Cu-Pd) + PdO deposits with 20-25 Pd atom % were obtained in which only 1-2 atom % of Pd were alloyed in the matrix. These (Cu-Pd) + PdO composites were mechanically stable and highly porous throughout their thickness (their pore volume being ca. 60% of the total volume). Their true surface area was some thousands of times higher than their geometric area.