Dinkel R, Braunschweig B, Peukert W (2016)
Publication Type: Journal article
Publication year: 2016
Book Volume: 120
Pages Range: 1673-1682
Journal Issue: 3
Applications of gold nanoparticles often demand that the particle's ligand shell is modified after particle formation. Obviously, there is a great need for a molecular understanding of this process which is often not accessible in situ. Here, we have applied second-harmonic light scattering (SHS) to investigate the ligand exchange at the surface of colloidal gold nanoparticles in situ and in real time. We demonstrate that the ligand exchange at the surface of citrate-covered Au nanoparticles with 3-mercapto-1-propanesulfonate (MPS) must be described by a fast (<100 s) and a slow reaction process (<23 min), which can be attributed to MPS adsorption on low- and high-coordinated Au surface sites. Using a modified Langmuir isotherm, the average Gibbs free energy of adsorption \textgreekDG ($-$46 kJ/mol) and the surface coverage \textgreekG (~3.5 \textgreekmmol/m2) for MPS on Au nanoparticles were determined. The latter was found to be much smaller compared to planar gold surfaces which points to coadsorption of MPS with citrate on high-coordinated sites, i.e., Au terraces. On more reactive low-coordinated Au sites, i.e., edge sites, citrate is easily replaced by MPS. In fact, we find that a substantial portion (49%) of the surface-adsorbed MPS is present on these low-coordinated sites.
APA:
Dinkel, R., Braunschweig, B., & Peukert, W. (2016). Fast and Slow Ligand Exchange at the Surface of Colloidal Gold Nanoparticles. Journal of Physical Chemistry C, 120(3), 1673-1682. https://dx.doi.org/10.1021/acs.jpcc.5b11055
MLA:
Dinkel, Rebecca, Björn Braunschweig, and Wolfgang Peukert. "Fast and Slow Ligand Exchange at the Surface of Colloidal Gold Nanoparticles." Journal of Physical Chemistry C 120.3 (2016): 1673-1682.
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