Litchi-peel-like hierarchical hollow copper-ceria microspheres: aerosol-assisted synthesis and high activity and stability for catalytic CO oxidation

Abstract

Copper-ceria is considered to be a promising system used in exhaust treatment due to its low cost and decent catalytic activity. Herein, we have developed novel litchi-peel-like hollow copper-ceria microspheres with varying Cu contents via an aerosol-assisted route. It is found that the dextrin in the spray solution plays a significant role as a sacrificial template and leads to the formation of this hierarchical hollow structure, in which higher surface area and active CuO_x species with higher dispersion result in better catalytic activity compared to the usual hollow samples. The litchi-peel-like sample with 20% Cu exhibits the best reactivity for CO oxidation, namely 50% conversion at 83 °C and 100% conversion at 120 °C. Importantly, this novel copper-ceria sample displays outstanding catalytic stability involving cycle stability, long-term stability and thermal stability, which is attributed to step-stabilized strong interaction between CuO_x species and CeO₂. The superior catalytic activity and stability beyond commercial 5 wt% Pt/Al₂O₃ provides it with the potential to be a substitute for Pt-based catalysts in practical applications.