Does a Higher Density of Active Sites Indicate a Higher Reaction Rate?

Area of Science:

• Catalysis and electrochemistry
• Materials science
• Chemical reaction engineering

Background:

• The prevailing view in catalysis posits a direct correlation between active site density and reaction rate.
• This principle is widely applied in the development of electrocatalysts for gas production.

Purpose of the Study:

• To investigate the relationship between active site density and reaction rate in electrocatalytic gas production.
• To challenge the conventional understanding of active site density's impact on reaction kinetics.

Main Methods:

• Utilizing molecular dynamics simulations to model the electrochemical formation of gas molecules.
• Analyzing the influence of varying active site densities on reaction rates.

Main Results:

• Demonstrated that a higher density of active sites does not necessarily lead to a higher reaction rate.
• Observed that high active site densities can, in fact, reduce the overall reaction rate.
• Identified gas molecule aggregation near active sites as the cause of this phenomenon.

Conclusions:

• The consensus view linking higher active site density to higher reaction rates is problematic for electrocatalytic gas production.
• Gas molecule aggregation near catalytic sites can hinder reaction kinetics.
• Findings provide a new perspective for designing improved electrocatalysts for gas-producing reactions.