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Dopant-Centered versus Intersite Synergistic Mechanisms in H2 Dissociation on Single-Atom Alloys
Ji Yan1, Tianhui Liu1,2
1School of Sciences, Great Bay University, Dongguan 523000, China.
The Journal of Physical Chemistry Letters
|July 7, 2026
Summary
Single-atom alloy (SAA) surfaces exhibit distinct H2 dissociation mechanisms. While some dopants enhance reactivity, high collision energies reveal unexpected performance limitations due to steric and azimuthal constraints.
Area of Science:
- Surface Science
- Chemical Dynamics
- Computational Chemistry
Background:
- Single-atom alloys (SAAs) are crucial in catalysis, offering tunable electronic and geometric properties.
- Understanding H2 dissociation on M1/Au(111) SAAs (M = Cu, Pd, Ag) is key to designing efficient catalysts.
Purpose of the Study:
- To elucidate the mechanisms of H2 dissociation on M1/Au(111) SAAs.
- To investigate the influence of dopant identity (Cu, Pd, Ag) on reaction pathways and energy barriers.
- To analyze the impact of collision energy on dissociation probabilities and identify performance crossovers.
Main Methods:
- Six-dimensional (6D) quantum dynamics simulations.
- Globally accurate neural network potential energy surfaces (NN PES).
- Analysis of steric and azimuthal constraints on reaction dynamics.
Main Results:
- Two distinct dissociation mechanisms identified: dopant-centered (Cu, Pd) and intersite synergistic (Ag).
- Doping generally reduces static energy barriers but leads to a high-energy crossover where pristine Au(111) outperforms SAAs.
- Dopant-induced steric and azimuthal constraints at hollow sites limit reactive phase space at high energies.
Conclusions:
- A classification framework for SAA reactivity is proposed, based on dopant-induced reactive region distributions.
- The findings highlight the complex interplay between dopant type, surface structure, and collision energy in catalytic reactions.
- Ag's unique synergistic mechanism underscores the potential for non-intuitive catalytic designs.
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