Fabrication of homogeneously Cu2+/La3+-doped CeO2 nanosheets and their application in CO oxidation
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 taking CPs as precursors. The final products not only retained stable nano-scaled 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 exhibit high activity achieving CO conversion of 60% at the temperature of 360 °C. When doped with Cu2+, remarkable improvement of catalysis is observed owing to the homogeneous incorporation of Cu2+ into CeO2 lattice. As catalytic active centers, uniformly dispersed CuO also produces more oxygen vacancies and improves oxygen mobility, which results in an enhancement in catalytic activity. The detected temperature with 50% CO conversion (T50) for Cu0.1Ce0.9O2-δ and Cu0.04Ce0.96O2-δ are 83 and 95 °C, respectively. In contrast, 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 system.