Toward tuning the surface functionalization of small ceria nanoparticles
Xing Huang1, Binghui Wang1, Eric A Grulke1
1Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506, USA.
The Journal of Chemical Physics
|February 25, 2014
Summary
Controlling ceria nanoparticle (CNP) catalysts needs understanding surface functional groups. Quantum mechanics and thermogravimetric analysis reveal hydroxyl and oxide groups influence CNP surface properties, enabling tunable catalysis.
Area of Science:
- Materials Science
- Surface Chemistry
- Nanotechnology
Background:
- Ceria nanoparticle (CNP) performance is dictated by surface structure and functional groups.
- Controlling CNP catalysts requires detailed knowledge of their surface properties.
Purpose of the Study:
- To investigate the surface functionalization of hydrothermally synthesized ceria nanoparticles.
- To establish a relationship between surface group density and formal charges in CNPs.
- To explore the potential for tuning CNP surface properties.
Main Methods:
- Thermogravimetric analysis (TGA) to quantify surface hydroxyl groups.
- Quantum mechanical calculations to model surface group density and distribution.
- Computational analysis considering various surface functionalizations (-OH, -Ox).
Main Results:
- Hydrothermally synthesized ∼30 nm CNPs exhibit 12.9 hydroxyl groups/nm(2).
- Quantum mechanical calculations predict a scaling relationship for surface group density.
- Agreement between predicted and measured densities is achieved when considering both -OH and -Ox groups.
Conclusions:
- CNP surface functionalization involves both hydroxyl and oxide groups.
- Surface group configurations are dependent on oxygen and hydrogen chemical potentials.
- CNP surface properties can be tuned by adjusting temperature and gas partial pressures (O2, H2O).
