Kuchibhatla Satyanarayana V N T, Karakoti Ajay S, Vasdekis Andreas E, Windisch Charles F, Seal Sudipta, Thevuthasan S, Baer Donald R
Environmental and Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA-99354, USA.
School of Engineering and Applied Science, Division of Biological and Life Sciences, School of Arts and Sciences, Ahmedabad University, Ahmedabad, Gujarat - 380009, India.
J Mater Res. 2019 Feb;34(3):465-473. doi: 10.1557/jmr.2018.490. Epub 2019 Feb 1.
Cerium oxide Nanoparticles (CNPs) are of significant interest to the scientific community due to their wide spread applications in a variety of fields. It is proposed that size dependent variations in the extent of Ce3+ and Ce4+ oxidation states of cerium in CNPs determines the performance of CNPs in application environments. To obtain greater molecular and structural understanding of chemical state transformations previously reported for ceria ≈ 3 nm nanoparticles (CNPs) in response to changing ambient conditions, microXRD and Raman measurements were carried out for various solution conditions. The particles were observed to undergo a reversible transformation from a defective ceria structure to a non-ceria amorphous oxy-hydroxide/peroxide phase in response to the addition of 30% hydrogen peroxide. For CNPs made up of ~8 nm crystallites, a partial transformation was observed and no transformation was observed for CNPs made up of ~ 40 nm crystallites. This observation of differences in size dependent transition behavior may help explain the benefits of using smaller CNPs in applications requiring regenerative behavior.
氧化铈纳米颗粒（CNPs）因其在各种领域的广泛应用而受到科学界的极大关注。有人提出，CNPs中铈的Ce3+和Ce4+氧化态程度的尺寸依赖性变化决定了CNPs在应用环境中的性能。为了更深入地从分子和结构层面理解先前报道的约3纳米氧化铈纳米颗粒（CNPs）在环境条件变化时的化学状态转变，对各种溶液条件进行了微XRD和拉曼测量。观察到这些颗粒在加入30%过氧化氢后会从有缺陷的氧化铈结构可逆转变为非氧化铈无定形羟基氧化物/过氧化物相。对于由约8纳米微晶组成的CNPs，观察到了部分转变，而对于由约40纳米微晶组成的CNPs则未观察到转变。这种尺寸依赖性转变行为差异的观察结果可能有助于解释在需要再生行为的应用中使用较小CNPs的好处。
