Synthesis of Copper-Promoted CeO₂ Catalysts

The urea method is explored for a high-yield preparation of CuO−CeO 2 catalysts precursors. Solutions containing urea, Ce(NO 3 ) 3, and Cu(NO 3 ) 2 were aged at 363 K for 5 h, achieving a quantitative coprecipitation in the form of amorphous Cu(II)−Ce(III) basic carbonates, with Cu(II) contents up to 40%. The mixed precursors were characterized by PXRD, SEM, EDS, FTIR, and TG. Upon mild thermal treatment under air atmosphere, i.e., T = 723 K, powders were readily converted into CuO-promoted nanometric ceria. No Tenorite (CuO) segregation is observed after annealing at 873 K. The binary oxides were characterized by means of temperature-programmed reduction (TPR) and a test reaction for the preferential oxidation of carbon monoxide (CO-PROX), achieving the best performance with samples containing around 20% in copper atoms.