Estimating Bulk-Composition-Dependent H<sub>2</sub> Adsorption Energies on Cu<sub><i>x</i></sub>Pd<sub>1–<i>x</i></sub> Alloy (111) Surfaces
- Publication date
- Publisher
Abstract
The bulk-composition-dependent dissociative
adsorption energy of
hydrogen on CuPd alloys has been measured experimentally and modeled
using density functional theory. The hydrogen adsorption energy cannot
be simply defined by a single reactive site or as a composition weighted
average of the pure metal components. We developed a modeling approach
that uses a basis of active sites weighted by a model site probability
distribution to estimate a bulk-composition-dependent adsorption energy.
The approach includes segregation under reaction conditions. With
this method, we can explain the composition-dependent adsorption energy
of hydrogen on Cu-rich alloy surfaces. In Pd-rich alloys, a Pd-hydride
phase may form, which results in deviations from trends on the metallic
alloy surface