Catalytic dissolution of ceria under mild conditions
Abstract
The dissolution of ceria is studied through a catalytic reduction process involving platinum nanoparticles in mild conditions at near ambient temperature. The deposition of platinum nanoparticles is made by sonication (Ar, 18 W cm−2, 20 kHz), and further dissolution is studied as a function of different parameters such as stirring, sonication, dissolution media and temperature. The dissolution is evaluated using UV-vis spectrophotometry, ICP-AES, and SEM. The quantitative dissolution of ceria can be performed in HNO3–HCOOH–[N2H5][NO3], HNO3–[N2H5][NO3] or H2SO4–HCOOH mixtures at 40 °C. Nevertheless, it is shown that the combined use of ultrasound with nitric media in the presence of platinum nanoparticles can lead to passivating phenomena resulting in a decrease of the dissolution rate.