以(CH₂OH)₂和H₂O的混合溶液为溶剂, Ce(NO₃)₃?6H₂O和In(NO₃)₃?4.5H₂O分别为Ce和In源, 采用溶剂热法在200 ℃下合成了前驱体, 再经500 ℃焙烧2 h制备了In³⁺掺杂的CeO₂粉末. 通过研究一系列In³⁺的添加浓度, 得出In³⁺掺杂CeO₂中In³⁺的固溶度为1% (摩尔分数). In³⁺掺杂对CeO₂形貌的影响不大, 固溶In³⁺前后的CeO₂颗粒形貌均为层状结构, 但当In³⁺的添加量高于固溶度时, 出现了细碎的第二相颗粒. In³⁺饱和掺杂浓度时CeO₂粉末的比表面积高于未掺杂的CeO₂, 达到100 m²/g, 当In³⁺的添加量大于等于3%时比表面积有所下降. In³⁺添加量对储氧能力的影响为: 首先, In³⁺的引入能够明显降低CeO₂的低温还原峰温度; 其次, 当In³⁺的添加量为饱和浓度1%时, CeO₂的低温储氧能力由未掺杂的3.6×10^-4 mol/g提高到4.4×10^-4 mol/g; 当In³⁺的浓度大于等于3%时, 试样的低温储氧能力先有所下降, 随后趋于稳定. 不同In³⁺添加量CeO₂粉末的晶格常数、氧空位浓度、比表面积和低温储氧能力都在1% In³⁺固溶度的位置出现了转折. 低温储氧能力与比表面积和氧空位浓度都有关联, 是二者综合作用的结果.

CeO₂ is an important rare earth oxide and can be used in automotive exhaust three-way catalysts on the basis of its oxygen storage capability. Ion doping is an effective method to enhance the oxygen storage capability of CeO₂. And when doping a cation whose size is smaller than Ce⁴⁺ and valence is lower than +4, it tends to evolve more defects. It is known that defects play important roles in enhancing the oxygen storage capability of CeO₂. Therefore, In ion was selected as a dopant cation which matches above two factors of size and valence. In this work, a series of CeO₂ with different content of In³⁺ were synthesized via a two-step process. The precursor was synthesized by a solvothermal method at 200 ℃ using a mixture solvent of (CH₂OH)₂ and H₂O, as well as Ce(NO₃)₃6H₂O and In(NO₃)₃?4.5H₂O as Ce and In sources, respectively. CeO₂ was obtained after the precursor was calcined at 500 ℃ for 2 h in air. It was found that the solid solubility of In³⁺ in CeO₂ was 1% (molar fraction). The doping of 1%In³⁺ in CeO₂ almost had no impact on the morphology of multilayered structure. However, a second phase of small particles appeared and there were some changes of the morphology of multilayered structure when the concentration of In³⁺ increased further. The specific surface area of the 1%In³⁺ solid solution was 100 m²/g, which was th highest among all the samples, and undoped CeO₂ (92 m²/g) ranked second. When the content of In³⁺ was above the solid solubility, i.e., 1%In³⁺, the specific surface area decreased. The low temperature oxygen storage capability could be improved from 3.6×10^-4 mol/g for undoped CeO₂ to 4.4×10^-4 mol/g for 1%In³⁺-doped CeO₂. When the In³⁺ content was greater than or equal to 3%, the low temperature oxygen storage capability decreased at the beginning, and then almost no change. Lattice parameter decreased and the concentration of Ce³⁺ and oxygen vacancy increased by the doping of In³⁺. Moreover, lattice parameter, the specific surface area, concentration of oxygen vacancy and low temperature oxygen storage capacity could mark a turning point for 1%In³⁺. It could be found that the low temperature oxygen storage capability was in relation to both the specific surface area and the concentration of oxygen vacancy of CeO₂. In addition, the low temperature reduction peaks shifted towards lower temperatures with the addition of In³⁺.