Fabrication of Au(1 1 1) facet enriched electrode on glassy carbon

A “two-phase protocol” is proposed to prepare gold electrode with controlled surface and crystallographic properties. Gold nanoparticles were first electrodeposited onto a glassy carbon (GC) electrode. Next, gold particles were allowed to be deposited by a colloidal chemical seeding process onto the previously electrodeposited gold nanoparticles on the GC electrode and thus Au-over-Au electrodes were fabricated. It was found that the surface area, crystallographic orientation and the surface morphology of the prepared electrodes can be controlled by adding acid or additive (I−) to the seeding media. An electrode ensemble with surface area of as high as 7.5 × 10−3 cm2 and ca. 60% Au(1 1 1) facet was fabricated by maintaining the seeding medium at pH 2.15. The application of the prepared electrode was demonstrated briefly in the electrochemical detection of arsenic(III) in water.