Investigation of the mechanism for the one-step synthesis of nano-cerium oxide via green electrolysis of cerium chloride

The precipitation-calcination synthesis process for cerium oxide (CeO 2 ) generates substantial quantities of ammonia nitrogen wastewater, posing significant environmental challenges. This study introduces an environmentally friendly and short-process cationic membrane electrolysis method that facilitates the direct conversion of CeCl 3 solution to CeO 2 nanoparticles in one-step. The investigation focused on the process parameters, including CeCl 3 concentration, current density, and electrolysis temperature. The findings demonstrate that, under optimal conditions (Ce 3+ concentration of 100 g/L, current density of 100 A/m 2 , and temperature of 303 K), CeO 2 was synthesized efficiently with an energy consumption of 2.53 kW·h/kg per unit mass. The physical and chemical properties of CeO 2 were characterized using advanced analytical techniques. The results revealed that the samples consisted of spherical powders with a grain size ranging from 15 to 43 nm and a uniform composition, exhibiting a specific surface area of 111 m 2 /g and a surface Ce 3+ content exceeding 10%, reaching up to 21%. Furthermore, this study examines the precipitation kinetics of CeO 2 . The electrolytic precipitation process of CeO 2 is governed by mass transfer diffusion and chemical reaction mixing, with an apparent activation energy of Ea = 17.73 kJ·mol -1 . This approach addresses environmental issues at their origin and holds significant potential for the synthesis of CeO 2 powder.