Related Experiment Video
Updated: Jul 12, 2026

Fabrication and Characterization of Thickness Mode Piezoelectric Devices for Atomization and Acoustofluidics
Published on: August 5, 2020
Three-site model for hydrogen adsorption on supported platinum particles: influence of support ionicity and particle
Michiel K Oudenhuijzen1, Jeroen A van Bokhoven, Jeffrey T Miller
1Department of Inorganic Chemistry and Catalysis, Debye Institute, Utrecht University, PO Box 80083, 3508 TB Utrecht, The Netherlands.
Abstract:
Pt L(3) X-ray absorption edge data on small supported Pt particles (N < 6.5) reveals that at very low H(2) pressure or high temperature the strongest bonded H is chemisorbed in an atop position. With decreasing temperature or at higher H(2) pressure only n-fold (n = 2 or 3) sites are occupied. At high H(2) pressure or low temperature, the weakest bonded H is positioned in an "ontop" site, with the chemisorbing Pt already having a stronger bond to a H atom in an n-fold site. DFT calculations show that the adsorption energy of hydrogen increases for Pt particles on ionic (basic) supports. The combination of the DFT calculations with hydrogen chemisorption data and the analysis of the Pt L(3) X-ray absorption spectra implies that both the H coverage and/or the type of active Pt surface sites, which are present at high temperature catalytic reaction conditions, strongly depend on the ionicity of the support. The consequences for Pt catalyzed hydrogenolysis and hydrogenation reactions will be discussed.
Related Concept Videos
Molecular Models
Surface Tension, Capillary Action, and Viscosity
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded by other molecules and are attracted equally in all directions by the cohesive forces within the liquid. However, the molecules on the surface of a liquid are attracted only by about one-half as many molecules. Because of the unbalanced molecular attractions on the surface molecules, liquids contract to form a shape that minimizes the number...
Precipitate Formation and Particle Size Control
The obtained precipitate should be either a pure substance of known composition or easily converted to one by a simple process, such as ignition or drying. In addition, the precipitate should be insoluble and easily filterable. In general, filterability...
The Kinetic Model of Gases
Adsorption Isotherms I

