Promotion effect of Sn in alumina-supported Pt catalysts for CO-PROX

In this work we have studied the effect of the addition of Sn to alumina-supported Pt catalysts towards the catalytic performance in CO-PROX reaction. Monometallic Pt and Sn catalysts supported on alumina, and bimetallic Pt–Sn supported on alumina (with Pt/Sn atomic ratios of 1.92, 0.53 and 0.28) was prepared by successive impregnation, with high dispersion of the metal. The addition of Sn to Pt does not substantially increase the activity in CO-PROX at low temperatures; however, the temperature interval where the CO conversion is maximum was significantly increased. The optimum Pt/Sn atomic ratio was found to be 0.53. In a wide operation window with respect to temperature, the catalyst with optimum Pt to Sn ratio shows a maximum CO conversion of 78% for λ = 2 with constant selectivity (about 40%) and with 31%CO yield. In the presence of either CO2 or H2O the performance of Sn promoted catalyst was seen to show improved activity.

Graphical AbstractFigure optionsDownload as PowerPoint slideResearch Highlights
► Presence of Pt is necessary to have high activity in CO-PROX.
► Sn-Pt/Al2O3 catalysts show wide operation window with almost constant selectivity.
► The optimum atomic Pt to Sn ratio is 0.53.
► Excess of oxygen (200%) is needed for complete removal of CO in the presence of H2.
► The individual presence of CO2 and H2O enhanced the activity and selectivity.