Direct in Situ Observation and Analysis of the Formation of Palladium Nanocrystals with High-Index Facets

Wenpei Gao, Yusheng Hou, Zachary D. Hood, Xue Wang, Karren More, Ruqian Wu, Younan Xia, Xiaoqing Pan, Miaofang Chi

Research output: Contribution to journalArticlepeer-review

42 Scopus citations

Abstract

Synthesizing concave-structured nanoparticles (NP) with high-index surfaces offers a viable method to significantly enhance the catalytic activity of NPs. Current approaches for fabricating concave NPs, however, are limited. Exploring novel synthesis methods requires a thorough understanding of the competing mechanisms that contribute to the evolution of surface structures during NP growth. Here, by tracking the evolution of Pd nanocubes into concave NPs at atomic scale using in situ liquid cell transmission electron microscopy, our study reveals that concave-structured Pd NPs can be formed by the cointroduction of surface capping agents and halogen ions. These two chemicals jointly create a new surface energy landscape of Pd NPs, leading to the morphological transformation. In particular, Pd atoms dissociate from the {100} surfaces with the aid of Cl- ions and preferentially redeposit to the corners and edges of the nanocubes when the capping agent polyvinylpyrrolidone is introduced, resulting in the formation of concave Pd nanocubes with distinctive high-index facets. Our work not only demonstrates a potential route for synthesizing NPs with well-defined high-index facets but also reveals the detailed atomic-scale kinetics during their formation, providing insight for future predictive synthesis.

Original languageEnglish
Pages (from-to)7004-7013
Number of pages10
JournalNano Letters
Volume18
Issue number11
DOIs
StatePublished - Nov 14 2018

Funding

W.G was supported by the Department of Energy (DOE), Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Grant DE-SC0014430, and partially by National Science Foundation (NSF) under Grant DMR-1506535 and DMR-1629270. Research was supported in part by the Center for Nanophase Materials Sciences at Oak Ridge National Laboratory (ORNL), which is a U.S. Department of Energy (DOE), Office of Science User Facility (W.G. and M.C.). Y.H. was supported by DOE-BES (Grant DE-FG02-05ER46237) and computing allocation by NERSC. Research supported in part by the Fuel Cell Technologies Office, U.S. DOE-EERE (K.M.). As a visiting student, X.W. was partially supported by the China Scholarship Council. Z.D.H. acknowledges a Graduate Research Fellowship award from the National Science Foundation (DGE-1650044) and the Georgia Tech-ORNL Fellowship. W.G was supported by the Department of Energy (DOE) Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Grant DE-SC0014430, and partially byNational Science Foundation (NSF)under GrantDMR-1506535 and DMR-1629270. Research was supported in part by the Center for Nanophase Materials Sciences at Oak Ridge National Laboratory (ORNL), which is a U.S. Department of Energy (DOE), Office of Science User Facility (W.G. and M.C.). Y.H. was supported by DOE-BES (Grant DE-FG02-05ER46237) and computing allocation by NERSC. Research supported in part by the Fuel Cell Technologies Office, U.S. DOE-EERE (K.M.). As a visiting student, X.W. was partially supported by the China Scholarship Council. Z.D.H. acknowledges a Graduate Research Fellowship award from the National Science Foundation (DGE-1650044) and the Georgia Tech-ORNL Fellowship.

Keywords

  • Liquid cell
  • catalyst
  • high index
  • in situ transmission electron microscopy
  • nanoparticle

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