Sintering of supported metal catalysts is a primary cause for deactivation at high temperatures. The study of its kinetics and of the changes in crystallite size distribution has been the subject of different studies in our group [1,2], and we have been able to show that apparent inconsistencies between leading models and experimental data were caused by limitations implicit to the models. We have developed improved models and equations both for the analysis of global kinetics and for the analysis of the experimental crystallite size distributions that provide not only an excellent match of the experimental data, but that have sound physical foundations.

In this work we analyze the sintering of supported Pt, Pd and Ni catalysts, and discuss the conditions needed for the observed crystallite size distributions to be a truly self – similar solution within the context of the Ostwald-ripening model. The implications for the mechanism of sintering are also discussed in the light of the resulting fits.

Significance

We provide guidelines for the analysis of sintering phenomena that can be useful in the design of more stable catalysts.

References

1.       Fuentes, G.A. and Gamas, E.D., in “Catalyst Deactivation 1991”, (C.H. Bartholomew and J.B. Butt, eds.), Stud. Surf. Sci. Catal., vol. 68,  p. 637, Elsevier, Amsterdam, 1991.

2.       Fuentes, G.A. and Salinas-Rodríguez, E., in “Catalyst Deactivation 2001”, (J.J. Spivey, G.W. Roberts and B.H. Davis, eds.), Stud. Surf. Sci. Catal., vol. 139, pp. 503, Elsevier, Amsterdam, 2001.