Modification of the surface electronic and chemical properties of Pt(111) by subsurface 3d transition metals

TLDR

Catalyst design, particularly for fuel cell electrocatalysts, depends on a detailed understanding of surface electronic and chemical properties. Density‑functional theory was employed to investigate how subsurface 3d transition metals alter the electronic and chemical characteristics of Pt(111) surfaces. Subsurface 3d metals broaden and lower the Pt(111) d‑band, weakening hydrogen and oxygen dissociative adsorption; the effect is strongest for early 3d metals, weakest for late 3d metals, can even make adsorption endothermic, and occurs without the need for lateral strain.

Abstract

The modification of the electronic and chemical properties of Pt(111) surfaces by subsurface 3d transition metals was studied using density-functional theory. In each case investigated, the Pt surface d-band was broadened and lowered in energy by interactions with the subsurface 3d metals, resulting in weaker dissociative adsorption energies of hydrogen and oxygen on these surfaces. The magnitude of the decrease in adsorption energy was largest for the early 3d transition metals and smallest for the late 3d transition metals. In some cases, dissociative adsorption was calculated to be endothermic. The surfaces investigated in this study had no lateral strain in them, demonstrating that strain is not a necessary factor in the modification of bimetallic surface properties. The implications of these findings are discussed in the context of catalyst design, particularly for fuel cell electrocatalysts.