Bifunctional catalytic material: An ultrastable and high-performance surface defect CeO2 nanosheets for formaldehyde thermal oxidation and photocatalytic oxidation

Eu-doped CeO2 nanosheets were obtained on Ti substrate by facile anodic electrodeposition and annealing in N2 atmosphere. The composition of the Eu cations doped into the CeO2 nanosheets can be easily tuned by adjusting the ratio of Eu to Ce, which promoted the formation of surface defects. Compared to pristine CeO2 nanosheets, the as-prepared 4% Eu/CeO2 nanosheets exhibited a much lower complete temperature (120 °C) of thermal oxidation for HCHO and a much longer stability as long as 100 h. Significantly, the Eu-doped CeO2 nanosheets also show a much improved photocatalytic performance for removing HCHO under the visible light irradiation. The excellent performance of 4% Eu/CeO2 nanosheets could be attributed to the abundance of surface defects, high specific surface area and large pore volume, high redox ability, narrowed band gap and enhanced optical absorption, and excellent response in the visible region of solar spectrum. Therefore, this work provides a facile and cost-effective strategy for the design and fabrication of multifunctional catalyst toward HCHO removal.