Hydrogen purification of actual syngas streams for energy applications: Au-Cu supported over nano-shaped CeO2 as stable catalysts for the carbon monoxide removal

[Display omitted] •CO-removal of an actual syngas stream from ethanol reforming was evaluated.•CeO2 nanostructure improves catalytic performance of AuCu/CeO2 catalysts.•High activity is favored when shaped CeO2 presents {111} and {100} lattice planes.•{110} planes favor CO2 selectivity, but they are unstable in continuous operation.•Fuel-cell grade hydrogen was achieved over an AuCu/CeO2 catalyst with polyhedra shape. Nano-shaped CeO2 (i.e., polyhedra, rods and cubes) and CeO2 without defined morphology were compared as supports of AuCu/CeO2 catalysts in the CO removal of actual syngas streams. Catalyst characterization indicates that oxygen vacancies, exposed CeO2 crystal planes, surface area and the interaction between active metals and support translate into changes in the catalytic performance on each nano-shape of CeO2. CeO2 nano-polyhedra and nano-rods show the higher activity and selectivity due to their high surface area and the presence of both {111} and {100} lattice planes. However, nano-rods are susceptible of losing CO2-selectivity under continuous operation due to the presence of an additional and unstable {110} lattice plane. Therefore, an AuCu catalyst supported on nano-polyhedra CeO2 ensures complete CO removal (i.e.,