Siyu Zhou1,Maochang Liu1,2,Sang-Il Choi1,Younan Xia1
Georgia Institute of Technology1,Xi’an Jiaotong University2
Siyu Zhou1,Maochang Liu1,2,Sang-Il Choi1,Younan Xia1
Georgia Institute of Technology1,Xi’an Jiaotong University2
Noble-metal nanocrystals enclosed by high-index facets are of growing interest due to their enhanced catalytic performance toward a variety of reactions. Herein, we report the deterministic synthesis of Pd nanocrystals encased by high-index facets by controlling the rate of deposition (<i>V<sub>deposition</sub></i>) relative to that of surface diffusion (<i>V<sub>diffusion</sub></i>). For octahedral seeds with truncated corners, a faster reduction rate (and thus deposition rate) than that of surface diffusion (<i>i.e.</i>, <i>V<sub>deposition</sub>/V<sub>diffusion</sub></i> > 1) led to the formation of concave trisoctahedra (TOH) with high-index facets. When the reduction was slowed down, in contrast, surface diffusion dominated the growth pathway. In the case of <i>V<sub>deposition</sub>/V<sub>diffusion</sub></i> ≈ 1, truncated octahedra with enlarged sizes were produced. When the reduction rate was between these two extremes, we obtained concave tetrahexahedra (THH) without or with truncation. Similar growth patterns were also observed for cuboctahedral seeds. When the Pd octahedra, concave TOH, and concave THH were tested for electrocatalyzing the formic acid oxidation (FAO) reaction, those with high-index facets were advantageous over the conventional Pd octahedra enclosed by {111} facets. This work not only contributes to the understanding of surface diffusion and its role in nanocrystal growth but also offers a general protocol for the synthesis of nanocrystals enclosed by high-index facets.