Determination of the Metal Dispersion of Supported Catalysts Using XPS

TARDITI, ANA MARIA; CORNAGLIA LAURA; MORI, FERNANDA

TOPICS IN CATALYSIS

SPRINGER/PLENUM PUBLISHERS

Lugar: New York; Año: 2019 vol. 62 p. 822 - 837

1022-5528

In this work, recent applications of XPS for the dispersion measurements of oxidic supports and metal catalysts were discussed. The most frequently used models, those of Kerkhof?Moulijn and Davis, were selected to give an overview of several applications in the study of catalysts, based on noble (Pd, Au, Ag, and Rh) and non-noble metals (Co, Ni). In the case of the dispersion of different promoters on the surface of oxidic supports, the Kerkhof?Moulijn model was often applied. Good correlations were achieved for high surface area Al2O3 supports modified by La, B and W. This model was also applied to analyze the dispersion of Co, Ni, Pd and Rh on oxidic supports, making it possible to propose the limit of monolayer formation for homogeneously distributed metal particles. The Davis model was developed for the estimation of metal particle sizes. This method considered the morphology of the metal particles and assumed a diamond-shaped support. The XPS results combined with the information obtained through other techniques showed the potential application of this model in the determination of metal particle sizes for Rh, Au, Pd and Ni based catalysts.