Bimetallic Au-Cu/CeO2 catalyst: Synthesis, structure, and catalytic properties in the CO preferential oxidation

The preparation of bimetallic Au-Cu catalysts via the decomposition of the double complex salt [Au(en)2]2[Cu(C2O4)2]3 · 8H2O is considered. It is found that this method of preparation allows us to selectively obtain Au0.4Cu0.6 solid solution nanoparticles on the surface of a support. The composition of the particles corresponds to the stoichiometry of the double complex salt. The properties of bimetallic Au-Cu/CeO2 catalyst and monometallic Au/CeO2 and Cu/CeO2 catalysts were studied during the preferential oxidation of CO in a mixture containing CO2 and H2O. The experiments were performed in a catalytic flow system within a temperature range of 50–250°C with a mixture of the following composition, vol %: CO, 1; O2, 0.6; H2O, 10; CO2, 20; H2, 60; and the balance, He. The weight hourly space velocity (WHSV) was 276000 cm3/(g h). The bimetallic catalyst made it possible to oxidize a considerably larger amount of CO with higher selectivity with CO2 and H2O in the mixture, relative to the monometallic catalysts. The preferential oxidation of carbon monoxide in the presence of hydrogen is a promising method for the deep purification of hydrogen-containing gas mixtures in order to remove carbon monoxide. The purified hydrogen-containing gas can be used to feed portable power units based on low-temperature proton-exchange membrane fuel cells, for the synthesis of ammonia, and for hydrogenation in fine organic synthesis.