Revealing an Intermediate Cu–O/OH Superstructure on Cu(110)

Abstract

Identifying the atomic structure and formation mechanism of intermediates during chemical transformations is challenging because of their short-lived nature. With a combination of microscopic and spectroscopic measurements and first-principles calculations, herein we report the formation of a metastable intermediate Cu–O/OH superstructure during the reaction of hydrogen with oxygen-covered Cu(110). This superstructure resembles the parent c(6 × 2)-O phase and can be termed as c(6 × 2)-(4O+2OH) with OH groups occupying the missing Cu sites between isolated Cu atoms. Using atomistic calculations, we elucidate the reaction pathways leading to the c(6 × 2)-(4O+2OH) formation via both molecular and dissociative H2 adsorption. These results demonstrate the complex surface dynamics resulting from the parallel reaction pathways and may open up the possibility of directing the reaction dynamics by deliberately manipulating transient surface structure and composition.

Atomistic Origins of Reversible Noncatalytic Gas–Solid Interfacial Reactions

“…The values of Hubbard parameters were U = 5 eV and J = 0 eV. The projector augmented-wave (PAW) , potential was used to describe the interaction between the ion and valence electrons, and the cut-off energy was set to 500 eV, similar to the previous calculations . In our calculations, the k -point grid within the Monkhorst–Pack scheme employed for the flat and stepped surfaces was 2 × 4 × 1.…”

“…The projector augmented-wave (PAW) 49,50 potential was used to describe the interaction between the ion and valence electrons, and the cut-off energy was set to 500 eV, similar to the previous calculations. 51 In our calculations, the k-point grid within the Monkhorst−Pack scheme employed for the flat and stepped surfaces was 2 × 4 × 1. All of the surface structures were fully relaxed using the conjugate gradient method, until the forces on each atom were less than 0.015 eV/Å.…”