# Direct Deoxygenation of Phenol over Fe-Based Bimetallic Surfaces Using On-the-Fly Surrogate Models

## TL;DR

This paper uses a fast computational method to study how phenol loses oxygen on iron-based surfaces, showing how adding metals like cobalt and nickel affects the reaction.

## Contribution

The study introduces a Gaussian process regression calculator that accelerates transition state searches with high accuracy for surface reactions.

## Key findings

- Subsurface Co and Ni substitutions maintain favorable DDO thermodynamics and kinetics similar to pure Fe(110).
- Top-layer Co and Ni substitutions increase C–O bond cleavage barriers and make DDO unfavorable.
- GPR-NEB provides up to 3 times speedup over DFT with energy barrier errors below 0.015 eV.

## Abstract

We present an accelerated
nudged elastic band (NEB) study of phenol
direct deoxygenation (DDO) on Fe-based bimetallic surfaces using a
recently developed Gaussian process regression (GPR) calculator. Our
test calculations demonstrate that the GPR calculator achieves up
to 3 times speedup compared to conventional density functional theory
calculations while maintaining high accuracy, with energy barrier
errors below 0.015 eV. Using GPR-NEB, we systematically examine the
DDO mechanism on pure Fe(110) and surfaces modified with Co and Ni
in both top and subsurface layers. Our results show that subsurface
Co and Ni substitutions preserve favorable thermodynamics and kinetics
for both C–O bond cleavage and C–H bond formation, comparable
to those on the pure Fe(110) surface. In contrast, top-layer substitutions
generally increase the C–O bond cleavage barrier, render the
step endothermic, and result in significantly higher reverse reaction
rates, making DDO unfavorable on these surfaces. This work demonstrates
the effectiveness of GRR-accelerated transition state searches for
complex surface reactions and provides insights into rational design
of bimetallic catalysts for selective deoxygenation.