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Enhanced reductibility of Ni and Ni + Pd in zeolite Y: Blocking of small cages with Ca2+ or Mg2+ ions

Research paper by Jennifer S. Feeley, Wolfgang M. H. Sachtler

Indexed on: 01 Sep '91Published on: 01 Sep '91Published in: Catalysis Letters



Abstract

Reducibility of zeolite encaged Ni2+ was found by temperature programmed reduction to increase in the following order Ni/NaY < Ni/MgY < Ni/CaY < (Pd + Ni)/NaY < (Pd + Ni)/MgY < (Pd + Ni)/CaY. In comparison with NaY supported samples, bimetallic MgY and CaY supported samples exhibited enhanced Pd2+ and Ni2+ reducibility as well as higher Hads/Me ° ratios after reduction below 500 °C. Temperature programmed reduction (TPR) and desorption (TPD) results indicate that Mg2+ and Ca2+ ions are occupying the small cages in the zeolite thus preventing the migration of the majority of Ni2+ and Pd2+ ions to these cages.