Compressive surface strained atomic-layer Cu2O on Cu@Ag nanoparticles
compressive surface strain, atomic-layer Cu2O, precise thickness-control, catalytic activity
Control of surface structure at the atomic level can effectively tune catalytic properties of nanomaterials. Tuning surface strain is an effective strategy for enhancing catalytic activity; however, the correlation studies between the surface strain with catalytic performance are scant because such mechanistic studies require the precise control of surface strain on catalysts. In this work, a simple strategy of precisely tuning compressive surface strain of atomic-layer Cu2O on Cu@Ag (AL-Cu2O/Cu@Ag) nanoparticles (NPs) is demonstrated. The AL-Cu2O is synthesized by structure evolution of Cu@Ag core-shell nanoparticles, and the precise thickness-control of AL-Cu2O is achieved by tuning the molar ratio of Cu/Ag of the starting material. Aberration-corrected high-resolution transmission electron microscopy (AC-HRTEM) and EELS elemental mapping characterization showed that the compressive surface strain of AL-Cu2O along the  and  directions can be precisely tuned from 6.5% to 1.6% and 6.6% to 4.7%, respectively, by changing the number of AL-Cu2O layer from 3 to 6. The as-prepared AL-Cu2O/Cu@Ag NPs exhibited excellent catalytic property in the synthesis of azobenzene from aniline, in which the strained 4-layers Cu2O (4.5% along the  direction, 6.1% along the  direction) exhibits the best catalytic performance. This work may be beneficial for the design and surface engineering of catalysts toward specific applications.
Tsinghua University Press
Xiyue Zhu,Hongpan Rong,Xiaobin Zhang,Qiumei Di,Huishan Shang,Bing Bai,Jiajia Liu,Jia Liu,Meng Xu,Wenxing Chen,Jiatao Zhang, Compressive surface strained atomic-layer Cu2O on Cu@Ag nanoparticles. NanoRes.2019, 12(5): 1187–1192