Polyelectrolytes assisted synthesis of gold/ceria catalyst for CO removal

Abstract

Ceria support was successfully synthesized by using anionic polyelectrolyte as a capping agent. In this work, the effects of capping agent concentration and synthesis method used on ceria particle size was investigated by using various concentrations of poly (4-styrenesulfonic acid-co-maleic acid) (PSS-co-MA) under magnetic stirring or sonication. The silver/ceria was prepared via sodium borohydride reduction and converted to gold/ceria via the redox reaction in an attempt to reduce amount of gold used compared to conventional catalyst preparations. Cerium (III) nitrate hexahydrate, silver nitrate, and hydrogen tetrachloroaurate (III) acid were used as the sources of cerium, silver, and gold, respectively. The prepared catalysts were characterized by particle size analyzer, nitrogen adsorption-desorption, FTIR, XRD and AAS. The catalytic activity and selectivity of the catalysts were also studied. The experimental results showed that the particle size of ceria was affected by the synthesis method and PSS-co-MA concentration. The increase in PSS-co-MA concentration induced a more negatively charged spread over the ceria surface to stabilize the sphere in solution. The smallest ceria particles (0.58±0.01 micron) were obtained by using 10 mM PSS-co-MA under magnetic stirring.