Stability and Activity of Cu-Au Nanoparticles in the Water-Gas Shift Reaction based on First Principles

Abstract

The water-gas shift reaction (WGSR) is an intermediate reaction in hydrocarbon reforming processes, considered one of the most important reactions for hydrogen production1, requiring efficient and stable catalysts. Bimetallic nanoparticles as CuAu, offer promising tunable reactivity, driven by the balance of their individual properties.2 In this contribution, we use density functional theory (DFT) calculations to investigate the surface stability of CuAu alloys for various Cu:Au ratios and predict their nanoparticle shapes, with the medium-term goal to predict their catalytic activity. We optimized Cu, Au, CuAu (L10), Cu₃Au (L12), and CuAu₃ (L12) phases and constructed slab models to evaluate their stability via surface energy calculations using the PBE and PBE-D3 functionals. The particle prediction shape was evaluated via the Wulff construction. On the most relevant facet for the CuAu alloy phase, i.e., CuAu (111), we are now evaluating the preferred adsorption site of key intermediates, as a previous step to determining the energy barriers for key reaction steps. This study provides insight into the thermodynamic stability of the main CuAu facets for catalyst design and provides the basis to subsequently understand the performance of these materials towards the WGSR.