Water-Induced Bimetallic Alloy Surface Segregation: A First Principle Study

TL;DR

This study uses density functional theory to analyze how water adsorption influences surface segregation in bimetallic alloys, revealing water's significant role in altering alloy surface compositions, especially for early and middle transition metals.

Contribution

It provides the first quantitative analysis of water's effect on surface segregation energies in Cu-based bimetallic alloys using DFT calculations.

Findings

Water adsorption induces strong segregation tendencies for early and middle transition metals in Cu alloys.

General trends in segregation energy changes due to water are established.

Results suggest re-examining water's effects on alloy surfaces in catalysis and materials science.

Abstract

Bimetallic alloys have drawn extensive attentions in materials science due to their widespread applications in electronics, engineering and catalysis. A very fundamental question of alloy is its surface segregation phenomenon. Many recent observations have shown that reactive gases or supports may have strong effects on alloy segregation. However, segregation in water, the most common solvent and environment, has not received enough attention. In this paper we give the quantitative descriptions on the surface segregation energies of 23 transition-metal impurities in Cu hosts under the conditions of water adsorption by performing density functional theory (DFT) calculations. The general trends in the changes of segregation energies caused by water adsorption are established. Our results show water adsorption could induce strong surface segregation tendencies for early and middle transition metals in Cu alloys. This finding not only prompts us to re-examine the potential effects of water on bimetallic alloy surfaces, but would be also very helpful as a guide for the further theoretical and experimental studies in this field.