Dioxide Cerium Catalyst And Catalytic Performance

Difference on the particle size and purity between nano-ceria particles prepared by hydrogen peroxide direct oxidation method, sodium-hydroxide precipitation method and ion-exchange method were investigated systematically. Then ceria that prepared by three method was used in photocatalytic oxidation of the micro-polluted water. Our experiment indicates that particles prepared by ion-exchange method have the smallest particle size and the highest purity. Under the condition of evenly adding 30ml strongly basic anion exchange resin in 16 minutes, 1g/L of the Ce3+ concentration, 30℃ of the exchange-temperature, and adding 2mL 0.49mol/L H2O2 one drop per five seconds, 60mg cubic crystal of ceria within 10 nanometer can be prepared. The lower roasting temperature leads to the smaller particle size during the preparation of microcrystal; Vacuum drying and vacuum roasting can also reduce the particle size. Particles prepared by ion-exchange method excel at photo-absorption efficiency and oxygen-adsorptive capacity than titanium dioxide. Using XPS for analysis of the ceira, it showed that the smaller of the particle size leads to a larger crystal lattice defect. The effect of ceria and titanium dioxide on photocatalytic degradation of phenol waste water had been compared. It showed that ceria excelled at the removal of phenol than titanium dioxide.