Hao Xiaodong, Zhang Shuai, Xu Yang, Tang Liangyu, Inoue Kazutoshi, Saito Mitsuhiro, Ma Shufang, Chen Chunlin, Xu Bingshe, Adschiri Tadafumi, Ikuhara Yuichi
Materials Institute of Atomic and Molecular Science, Shaanxi University of Science and Technology, Xi'an 710021, China.
WPI-Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
Nanoscale. 2021 Jun 17;13(23):10393-10401. doi: 10.1039/d1nr01746b.
Surfactant plays a remarkable role in determining the growth process (facet exposition) of colloidal nanocrystals (NCs) and the formation of self-assembled NC superstructures, the underlying mechanism of which, however, still requires elucidation. In this work, the mechanism of surfactant-mediated morphology evolution and self-assembly of CeO2 nanocrystals is elucidated by exploring the effect that surfactant modification has on the shape, size, exposed facets, and arrangement of the CeO2 NCs. It is directly proved that surfactant molecules determine the morphologies of the CeO2 NCs by preferentially bonding onto Ce-terminated {100} facets, changing from large truncated octahedra (mostly {111} and {100} exposed), to cubes (mostly {100} exposed) and small cuboctahedra (mostly {100} and {111} exposed) by increasing the amount of surfactant. The exposure degree of the {100} facets largely affects the concentration of Ce3+ in the CeO2 NCs, thus the cubic CeO2 NCs exhibit superior oxygen storage capacity and excellent supercapacitor performance due to a high fraction of exposed active {100} facets with great superstructure stability.
表面活性剂在决定胶体纳米晶体（NCs）的生长过程（晶面暴露）和自组装NC超结构的形成中起着显著作用，然而其潜在机制仍有待阐明。在这项工作中，通过探索表面活性剂修饰对CeO2纳米晶体的形状、尺寸、暴露晶面和排列的影响，阐明了表面活性剂介导的CeO2纳米晶体形态演变和自组装的机制。直接证明了表面活性剂分子通过优先键合到Ce端的{100}晶面上决定CeO2纳米晶体的形态，随着表面活性剂用量的增加，晶体形态从大的截顶八面体（主要暴露{111}和{100}晶面）变为立方体（主要暴露{100}晶面）和小立方八面体（主要暴露{100}和{111}晶面）。{100}晶面的暴露程度在很大程度上影响CeO2纳米晶体中Ce3+的浓度，因此立方CeO2纳米晶体由于大量暴露的具有优异超结构稳定性的活性{100}晶面而表现出卓越的储氧能力和优异的超级电容器性能。
