BACKGROUND: The metal dispersed over a support can be present as small crystallites with sizes less than 5 nm. The smaller crystallites favour aromatization while larger crystallites favour cracking/hydrogenolysis. Sintering results in the agglomerization of smaller metal crystallites. Correlation of size with aromatization selectivity was investigated. RESULTS: The primary products of n-heptane reforming on fresh Pt were methane, toluene, and benzene, while on fresh Pt-Re, the only product was methane. Both catalysts exhibited enhanced aromatization selectivity at different oxygen sintering temperatures. The reaction products ranged from only toluene at 500 degrees C sintering temperature to methane at a sintering temperature of 650 degrees C with no reaction at 800 degrees C for the Pt/Al2O3 catalyst. On Pt-Re/Al2O3 catalyst, methane was the sole product at a sintering temperature of 500 degrees C while only toluene was produced at a sintering temperature of 800 degrees C. CONCLUSION: This is the first time that sintering has been used to facilitate aromatization of supported Pt and Pt-Re catalysts. A superior selectivity behaviour associated with bi-metallic Pt catalysts is established. It was found that no reaction occurred on Pt catalyst after sintering at 800 degrees C whereas sintering Pt-Re at 800 degrees C promoted aromatization solely to toluene. (c) 2008 Society of Chemical Industry.