CRYSTALLOGRAPHIC HABIT OF GOLD PARTICLES GROWN ON ELECTRODES IN ACIDIC SOLUTIONS AT DIFFERENT ELECTRODE-POTENTIALS

Fine gold particles grown on the electrode in various acid solutions a t different electrode potentials have been studied by means of transmi ssion electron microscopy. It was found that the octahedral f.c.c. sin gle crystal particles are grown at positive electrode potentials (SCE) , but the pentagonal decahedron and hexagonal icosahedron particles ar e grown preferentially at negative electrode potentials (SCE). Differe nt shapes and structures of gold particles formed at different electro de potentials are attributed to the surface energy of the growing part icles, which may be influenced by the electrode potential. The (1 x 1) structure may correspond to lower surface energy structure at positiv e electrode potentials, but the surface at negative electrode potentia ls prefers to take the hexagonal arrangement of the atoms to lower the surface energy. Anions showed different influences on the growth of p articles, so the effect of anions is discussed in this paper.