Comparison of different synthesis techniques of supported platinum catalysts and their sintering studies

In the present study, alumina-supported platinum nanocatalysts were synthesized by different techniques to get high dispersion, preferential distribution of nanosize platinum near the pore mouth of support and effective protection against sintering of platinum particles. Various methods were used to characterize the catalysts and it was found that preparation technique greatly affects the dispersion of platinum particles in the catalysts. When ammonia was present in the impregnating solution it gave higher values of percent platinum exposed, better dispersion and preferential distribution of platinum near the surface of catalysts. Sintering phenomenon was studied in detail for our prepared catalysts at various temperatures. It was observed that all the catalysts suffered from sintering at 773 K and it was enhanced at higher temperature of 973 K. Sintering kinetics was established and power law type of rate equation was fitted to get the rate equation.