VERFAHREN ZUR HERSTELLUNG VON LEGIERTEN KATALYSATOREN.

摘要

PCT No. PCT/US91/04398 Sec. 371 Date Aug. 8, 1991 Sec. 102(e) Date Aug. 8, 1991 PCT Filed Jun. 21, 1991.Adjustment of the noble metal catalytic activity in the production of noble metal alloyed catalyst preparation using alloying metals capable of multiple valence states improves the alloying metal loading. A noble metal is precipitated from a liquid onto a support. Prior to the addition of an alloying metal which is capable of a low valence state having low solubility and a high valence state having high solubility, the catalytic activity of the noble metal precipitate is reduced. Reduction is accomplished by adjusting the temperature and/or pH of the liquid such that a minimal amount of the alloying metal will be converted from the lower to the higher valence state. By maintaining the alloying metal in the lower valence state, a greater amount of the alloying metal which has been dissolved into the liquid is precipitated onto the support, thereby attaining high loadings, reducing waste of the alloying metal, making the loadings predictable, and making the waste liquid more environmentally sound.