Quantum Monte Carlo with ground-state input to investigate methane reactions on supported metal film catalysts

TL;DR

This paper demonstrates how Quantum Monte Carlo methods, incorporating ground-state information via a Jastrow factor, can accurately model methane dissociation on nickel catalysts, providing detailed insights into activation barriers and adsorption sites.

Contribution

It introduces a novel approach to include electron correlation in QMC calculations for heterogeneous catalysis using a generic Jastrow factor, improving accuracy in modeling methane reactions.

Findings

Accurate activation barrier for methane C-H bond stretching.

Identification of adsorption sites for CH3- and H- on nickel.

Method enhances predictive modeling of catalytic processes.

Abstract

Nowadays, there is pressing demand for sustainable energy sources, or clean and 'green' fuel and hydrogen is a perfect candidate. It can be made by dissociating methane with the energy input compensated by metal-hydrogen bond formation. Industry uses Nickel supported on $\gamma$-alumina for this rate-limiting step. This work shows how to use Quantum Monte Carlo calculations to take (user-guided) information summarising chemistry of heterogeneous catalysis from a generic Jastrow factor, that allows electron correlation to be included in the density. This, in turn, gives accurate values of properties, in particular the activation barrier for stretching one methane C-H bond, before adsorbing CH3- and H- on vicinal nickel atoms in the close-packed (111) plane. The CH3- co-ordinates to a hollow site defined by three Ni atoms and, new to this work, another Ni-atom co-ordinates the H-atom from the dissociation.