Facet-Dependent Surface Charge and Hydration of Semiconducting Nanoparticles at Variable pH

Shaoqiang Su, Igor Siretanu, Dirk van den Ende, Bastian Mei, Guido Mul, Frieder Mugele*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

38 Citations (Scopus)
167 Downloads (Pure)


Understanding structure and function of solid–liquid interfaces is essential for the development of nanomaterials for various applications including heterogeneous catalysis in liquid phase processes and water splitting for storage of renewable electricity. The characteristic anisotropy of crystalline nanoparticles is believed to be essential for their performance but remains poorly understood and difficult to characterize. Dual scale atomic force microscopy is used to measure electrostatic and hydration forces of faceted semiconducting SrTiO3 nanoparticles in aqueous electrolyte at variable pH. The following are demonstrated: the ability to quantify strongly facet-dependent surface charges yielding isoelectric points of the dominant {100} and {110} facets that differ by as much as 2 pH units; facet-dependent accumulation of oppositely charged (SiO2) particles; and that atomic scale defects can be resolved but are in fact rare for the samples investigated. Atomically resolved images and facet-dependent oscillatory hydration forces suggest a microscopic charge generation mechanism that explains colloidal scale electrostatic forces.

Original languageEnglish
Article number2106229
JournalAdvanced materials
Issue number52
Early online date5 Oct 2021
Publication statusPublished - 29 Dec 2021


  • atomic force microscopy
  • atomically resolved images
  • facet-dependent surface charges
  • faceted semiconducting SrTiO nanoparticles
  • hydration structures
  • nanoparticles
  • semiconductor electrolyte interfaces
  • UT-Hybrid-D


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