Size effect of Pd clusters on hydrogen adsorption
Hung-Wen Lee1, Chun-Ming Chang
1Department of Physics, National Dong Hwa University, Hualien 974, Taiwan.
Summary
The size of palladium (Pd) clusters impacts hydrogen adsorption. Smaller Pd clusters exhibit stronger hydrogen bonding due to electronic structure changes, aligning with experimental data.
Area of Science:
- Materials Science
- Physical Chemistry
- Computational Chemistry
Background:
- Hydrogen adsorption on metal clusters is crucial for catalysis.
- Understanding size-dependent properties of nanoparticles is key for material design.
Purpose of the Study:
- Investigate the influence of palladium cluster size on hydrogen adsorption.
- Elucidate the underlying electronic mechanisms governing this interaction.
Main Methods:
- Density functional theory (DFT) calculations were employed.
- Molecular dynamics (MD) simulations were utilized to study adsorption behavior.
- Electronic structure analysis was performed to understand bonding.
Main Results:
- Hydrogen molecules dissociatively adsorb on palladium clusters, favoring hollow sites.
- Adsorption energy increases as palladium cluster size decreases.
- A negative shift in the d-band center towards the Fermi energy correlates with decreased cluster size.
Conclusions:
- Palladium cluster size significantly affects hydrogen adsorption strength and mechanism.
- The d-band center shift is identified as the key factor for enhanced hydrogen bonding in smaller clusters.
- Findings provide insights into designing efficient catalytic materials based on metal cluster size.
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