Effect of lanthanum on the catalytic properties of PtSn/γ-Al2O3 bimetallic catalysts prepared by successive impregnation and controlled surface reaction

摘要: Abstract Bimetallic PtSn/ γ -Al 2 O 3 –La catalysts were prepared by two comparative methods, successive impregnation (SI) and controlled surface reaction (CSR). FTIR-pyridine adsorption revealed a decrease in support acidity as function of lanthanum content. Oxidized Pt 2+ was identified CO-FTIR chemisorption XPS spectra on SI. When the CSR preparation method used, reduced 0 observed oxidized not detected. As content increased diminution cyclohexane dehydrogenation n -heptane conversion observed. Low hydrogenolysis high selectivity to C 7 -olefins obtained both preparations. It is proposed that SI stabilizes platinum an oxidation state, , diminishes acidity. In preparations effect limited inhibit hence bifunctional reactions occurring during conversion.