Fabrication of homogeneously Cu2+/La3+-doped CeO2 nanosheets and their application in CO oxidation

Abstract

Nanosheets of coordination polymers (CPs) were synthesized via a facile and one-step complexing-coprecipitation (CC) method. Upon calcination, pure CeO₂ and homogeneously La³⁺- or Cu²⁺-doped CeO₂ products were fabricated by using CPs as precursors. The final products not only retained a stable nano-scale sheet-shaped morphology of their CP precursors, but also possessed high catalytic activity towards CO oxidation. Superior to commercial ceria with negligible catalytic activity, the synthesized CeO₂ nanosheets exhibited high activity achieving a CO conversion of 60% at a temperature of 360 °C. When doped with Cu²⁺, remarkable improvement of catalysis is observed owing to the homogeneous incorporation of Cu²⁺ into the CeO₂ lattice. As a catalytically active center, uniformly dispersed CuO also produces more oxygen vacancies and improves oxygen mobility, which results in an enhancement in catalytic activity. The detected temperatures with 50% CO conversion (T₅₀) for Cu_0.1Ce_0.9O_2−δ and Cu_0.04Ce_0.96O_2−δ are 83 and 95 °C, respectively. In contrast, the catalytic test for La³⁺ doped ceria reveals a decreased activity compared with un-doped ceria. We believe that the Cu²⁺-doped CeO₂ with superior catalytic performance can also be applied to other catalytic systems.