First-Principles Investigation of Adsorbate–Adsorbate Interactions on Ni(111), Ni(211), and Ni(100) Surfaces

Periodic density functional theory calculations were employed to investigate the coadsorption patterns between CO and key water gas shift reaction (WGSR) intermediates, i.e., H₂O, H, OH, O, and COOH, on Ni(111), Ni(100), and Ni(211) single-crystal surfaces. It has been shown that although the nature of these adsorbate pair interactions are predominantly repulsive, as commonly assumed in the literature, the interaction pattern for each adsorbate pair can be complicated by facet lattice structures and potential intermolecular hydrogen bonds, which play an unsubtle role in influencing the WGSR redox and carboxyl pathways. This investigation can enrich our descriptions of the adsorbate lateral interactions for surface chemistry modeling and will also provide theoretical insights into tuning the properties of nanoscale nickel catalysts by manipulating the surface structure and morphology for hydrogen fuel production