Cerium-zirconium-palladium nanopowder catalyst and preparation and application thereof

The invention relates to a preparation method for a cerium-zirconium-palladium nanopowder catalyst. The preparation method comprises the following steps: dissolving a cerium source and a zirconium source in absolute ethanol, and adding P123 template agent to obtain sol; adding palladium nitrate; keeping constant temperature of 35DEG C and constant relative humidity of 40 percent, and performing evaporation induction to form gel; drying at the temperature of 100DEG C; calcining at the temperature of 400DEG C for 4 hours at the temperature rise rate of 1DEG C per minute; and ensuring that the atomic mole ration of cerium to zirconium is 8:2, the palladium loading quantity is 0.1 to 5 weight percent, and a ratio of the cerium source and the zirconium source to the absolute ethanol to the P123 is 10mmol:20ml:1g. The catalyst is suitable for catalytic elimination of CO in flue gas discharged by a catalytic cracking catalyst regeneration device and Co in tail gas of motor vehicles and has the advantages of large sp