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Pt/Nb₂O₅ catalysts were prepared on a reducible support by ion exchange and incipient wetness of different platinum salts. The Pt/Nb₂O₅/Al₂O₃ catalysts were prepared with several loading of niobium oxide over alumina, aiming different surface coverages and platinum dispersions. These catalysts were characterized by using different techniques: TPR, DRS, chemisorption of H₂, CO, CO₂ and pyridine. The catalytic activity was evaluated in the n-heptane conversion. Platinum oxide was the main surface precursor on the Nb₂O₅ supported catalysts, while a oxychloroplatinum surface complex was the precursor for Pt/Nb₂O₅/Al₂O₃ catalysts. These different precursors promote the formation of different platinum particle sizes, being the Pt/Nb₂O₅/Al₂O₃ samples more disperse. After high temperature of reduction, the platinum adsorption capacity decrease on all the samples, due to the reduction of Nb₂O₅, and …