Surfactant-Mediated One-Pot Method To Prepare Pd–CeO₂ Colloidal Assembled Spheres and Their Enhanced Catalytic Performance for CO Oxidation

Abstract

A simple, one-pot method to fabricate ordered, monodispersed Pd–CeO₂ colloidal assembled spheres (CASs) was developed using the surfactant-mediated solvothermal approach, which involves a tunable self-assembled process by carefully controlling different chemical reactions. The evolution process and formation mechanism of the CASs were thoroughly investigated by time-controlled and component-controlled experiments. For CO oxidation, this CAS nanocatalyst exhibited much higher catalytic activity and thermal stability than Pd/CeO₂ prepared by an impregnation method, and its complete CO conversion temperature is ∼120 °C. The enhanced catalytic performance for CO oxidation could be attributed to the synergistic effect of highly dispersed PdO species and Pd²⁺ ions incorporated into the CeO₂ lattice. For this CAS catalyst, each sphere can be viewed as a single reactor, and its catalytic performance can be further improved after being supported on alumina, which is obviously higher than results previously reported. Furthermore, this method was used to successfully prepare M–CeO₂ CASs (M = Pt, Cu, Mn, Co), showing further that this is a new and ideal approach for fabricating active and stable ceria-based materials