In situ video STM studies of the hydrogen-induced reconstruction of Cu(100): potential and pH dependence.

The surface structure of Cu(100) electrodes in perchloric acid solutions of pH 1 to 3 was studied in the potential range of hydrogen evolution by video-rate scanning tunneling microscopy, focusing on the recently reported hydrogen-induced surface reconstruction [H. Matsushima et al., J.

Reconstruction of Cu(100) electrode surfaces during hydrogen evolution.

Electrochemical hydrogen evolution on (100)-oriented copper electrodes is shown to induce a novel surface reconstruction, which substantially influences the rates of this electrochemical reaction. As revealed by in situ video-STM the formation of this phase starts with lateral displacements of Cu surface atoms from lattice positions, resulting in stripe-like structures, followed by expansion of the surface lattice along the stripe direction.