Single crystalline thin films as a novel class of electrocatalysts

Abstract

The ubiquitous use of single crystal metal electrodes has garnered invaluable insight into the relationship between surface atomic structure and functional electrochemical properties. However, the sensitivity of their electrochemical response to surface orientation and the amount of precious metal required can limit their use. Herein, a generally applicable procedure for the production of thin metal films with a large proportion of atomically flat (111) terraces without the use of an epitaxial template is presented. Thermal annealing in a controlled atmosphere induces long-range ordering of magnetron sputtered thin metal films deposited on an amorphous substrate. The ordering transition in these thin metal films yields characteristic (111) electrochemical signatures using a minimal amount of material and provides an adequate replacement for oriented bulk single crystals. This procedure could be generalized towards a novel class of practical multimetallic thin film-based electrocatalysts with tunable near-surface compositional profiles and morphologies. Annealing of atomically corrugated sputtered thin film Pt-alloy catalysts yields an atomically smooth structure with highly crystalline, (111)-like ordered and Pt segregated surface that displays superior functional properties, bridging the gap between extended/bulk surfaces and nanoscale systems. ©2013 SCS.