Surface-controlled galvanic replacement for the development of Pt-Ag nanoplates with concave surface substructures

Abstract

Galvanic replacement, a spontaneous redox reaction arising from contact between a nanotemplate and a replacing ion, has been widely used for its convenience, stability, and ability to form various complex nanostructures. In this study, the two-dimensional nanosurface adsorption of polymeric micelles is performed for substructure formation through advanced galvanic replacement strategies. Polymeric micelles adsorbed on the nanotemplate surface form a nano-array structure of hydrophobic and hydrophilic domains, resulting in surface controlled galvanic replacement and the formation of concave surface substructures. The hydrophobic domain formation and blockage region expansion due to nanotemplate curvature and solvent composition contributes greatly to the surface substructure formations. The results can be summarized as a successful attempt to design the nanostructure by coordinating all potential factors involved in conventional galvanic replacement to create an unprecedented high-complexity nanostructure. Manufactured Pt-Ag nanoplates with concave surface substructures exhibited the successful hydrogen evolution electrocatalytic efficiency as demonstration. The Pt-Ag nanoplates with concave surface substructures exhibit the enhanced HER activity in strong acidic solutions with a low Tafel slope. The enhancement of the HER performance can be attributed to concave surface substructures, which greatly improve the edge sites and defects, resulting in a high density of exposed active sites. The galvanic replacement-based material design strategy demonstrated here exemplifies a novel and versatile approach to developing electrocatalysts with high activity and durability for advanced electrochemical water-splitting systems.