Design of 3-Dimensionally Self-Assembled CeO 2 Nanocube as a Breakthrough Catalyst for Efficient Alkylarene Oxidation in Water

This paper reports preparation of CeO 2 nanocrystals by using oleic acid as a surfactant. A strong coordinating property of oleic acid toward (100) planes of the nanocrystals facilitated three-dimensional (3D) assembly via oriented attachment of the nanocrystal building blocks to form (100) surface exposed porous cubic ceria by sharing {111} facets. As-synthesized materials were characterized by HRTEM, SEM, XRD, FTIR, Raman spectroscopy, and BET surface area analyzer. 3D morphology was established by STEM-HAADF technique and dark-field TEM. As-synthesized CeO 2 nanocubes showed breakthrough in catalytic performance, enabling quantitative p X conversion and absolute selectivity in terephthalic acid (>99%). The presence of higher concentrations of oxygen vacancies (1.42 × 10 21 cm –3 ), owing to preferred exposed surfaces and lower individual crystallites size (6 nm), and larger surface area and pore size have been reasoned for high catalytic effectiveness. The catalyst recyclability experiments showed only 6% activity loss in TA yield in the fourth cycles.