Real-Space Formation and Dissipation Dynamics of Hexagonal Reconstruction on Au(100) in Aqueous Media as Explored by Potentiodynamic Scanning Tunneling Microscopy
Abstract
The electrode potential-induced formation and dissipation dynamics of the hexagonal ('hex') reconstruction on ordered Au(100) in perchloric and sulfuric acid electrolytes has been studied by means of in-situ scanning tunneling microscopy (STM). The real-space/real-time evolution of surface structures associated with the potential-dependent hex left and right arrows (1 x 1) phase transition was examined on timescales down to ca 1 s by acquiring STM images during appropriate potential sweeps and steps (dubbed here 'potentiodynamic STM'). Extensive hex domains can be formed by slow cooling following flame annealing and/or by holding the potential at values significantly below the potential of zero charge for the (1 x 1) surface. The sharp removal of the reconstruction seen voltammetrically, during positive-going potential sweeps, is accompanied by rapid (< 1 s) formation of arrays of ordered (1 x 1) clusters, created from the release of the ca 24% additional gold atoms utilized in the (5 x 27) and related hex structures compared with the (1 x 1) substrate. These clusters are significantly, twofold, larger (ca 4-6 nm) when formed in sulfuric acid electrolyte, due probably to an enhanced surface mobility in the presence of adsorbed sulfate.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1993
- Accession Number
- ADA266138
Entities
People
- Antoinette Hamelin
- Gregory J. Edens
- Michael J. Weaver
- Xiaoping Gao
Organizations
- Purdue University