Limits to scaling relations between adsorption energies?

Area of Science:

• Surface science
• Computational chemistry
• Catalysis

Background:

• Linear scaling relations (LSRs) are widely used to understand trends in catalytic activity and selectivity.
• However, LSRs are not universally applicable, particularly for chemisorption energies of small molecules on transition metal surfaces.
• A key example is the breakdown of scaling between carbon and oxygen adsorption energies.

Purpose of the Study:

• To investigate the fundamental reasons behind the lack of linear scaling between carbon and oxygen chemisorption energies.
• To develop a predictive model for the applicability of scaling relations in heterogeneous and electro-catalysis.
• To introduce a general descriptor for determining if two adsorbates will exhibit scaling behavior.

Main Methods:

• Utilized the d-band model for adsorbate chemisorption.
• Combined a modified Newns-Anderson hybridization energy with an effective orthogonalization term.
• Developed a new descriptor to predict adsorbate scaling relations a priori.

Main Results:

• Identified differing re-normalized adsorbate valence energies as the cause for the lack of scaling between carbon and oxygen.
• Successfully modeled chemisorption using the d-band model with modifications.
• Established a general descriptor to predict the likelihood of scaling between different adsorbates.

Conclusions:

• The breakdown of linear scaling relations for certain adsorbates is due to differences in their electronic structure and interaction with metal surfaces.
• The developed model and descriptor offer a new tool for predicting adsorbate behavior and designing catalysts.
• This work advances the understanding of surface chemistry and the design principles for heterogeneous and electro-catalysis.