Aluminumphosphate molecular sieves supported Pt–Co catalysts for the preferential oxidation of CO in H2-rich gases

A series of aluminumphosphate molecular sieves supported platinum–cobalt catalysts were prepared and tested for the preferential oxidation of CO in H2-rich gases. The catalysts were characterized by XRD, HRTEM, EDX, TPR and XPS techniques. The optimized catalysts were highly active and selective, CO could be purified below 10 ppm in the reaction temperature range of 110 °C–125 °C under 1% CO, 1% O2, 12.5% CO2, 15% H2O, 50% H2 in volume and N2 balance at the space velocity of 24,000 mL gcat−1 h−1. Pt–Co/CoAPO-5 exhibited the best catalytic performance and Pt–Co/AlPO-5 was the most active catalyst at low reaction temperature, in which particles of Pt–Co alloy were formed and the particles were highly dispersed on the surface of the support. The high activity could be attributed to the Pt–Co nano-partilces with small sizes. The enlarged temperature window for CO purification should be ascribed to the loaded cobalt oxide. Substitution of cobalt ions for aluminium ions has obvious influence on the interaction between the support and platinum/cobalt species.

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► Pt–Co alloy were formed and the particles were highly dispersed.
► Substitution of cobalt ions for aluminium ions has obvious influence on the interaction between the support and platinum/cobalt species.
► CoAPO supported Pt–Co catalysts showed very good catalytic performance for CO preferential oxidation.
► The enlarged temperature window for CO purification is supposed to be attributed to the loaded cobalt oxide.