Selective removal of CO from hydrogen-rich stream over CuO/Ce xSn 1−xO 2–Al 2O 3 catalysts

Abstract

The solid solutions of Ce x Sn 1− x O 2 incorporated with alumina to form Ce x Sn 1− x O 2–Al 2O 3 mixed oxides, by the suspension/co-precipitation method, were used to prepare CuO/Ce x Sn 1− x O 2–Al 2O 3 catalysts for the selective oxidation of CO in excess hydrogen. Incorporating Al 2O 3 increased the dispersion of Ce x Sn 1− x O 2, but did not change their main structures and did not weaken their redox properties. Doping Sn 4+ into CeO 2 increased the mobility of lattice oxygen and enhanced the activity of the 7%CuO/Ce x Sn 1− x O 2–Al 2O 3 catalyst in the selective oxidation of CO. The selective oxidation of CO was weakened as the doped fraction of Sn 4+ exceeded 0.5. Incorporating appropriate amounts of Sn 4+ and Al 2O 3 could obtain good candidates 7%CuO/Ce x Sn 1− x O 2–Al 2O 3(20%), 1– x=0.1–0.5, for a preferential oxidation (PROX) unit in a polymer electrolyte membrane fuel cell system for removing CO. Its activity was comparable with, and its selectivity was much larger than, that of the noble catalyst 5%Pt/Al 2O 3.