2003 Volume 44 Issue 4 Pages 727-730
Bare and anodically oxidized Ni(110) surfaces in 0.05 kmol m−3 Na2SO4 (pH = 6.5) and 0.01 kmol m−3 NaOH (pH = 12) aqueous solution have been investigated by in-situ electrochemical atomic force microscopy (EC-AFM) with atomic resolution. We have succeeded in in-situ observation of unreconstructed Ni(110)-(1×1) structures in both 0.05 kmol m−3 Na2SO4 and 0.01 kmol m−3 NaOH solution. Under passive region, we have observed well-ordered structures differing from those of the bare surfaces and we found that surface structure of anodically oxidized Ni(110) in 0.05 kmol m−3 Na2SO4 solution agrees with NiO(110), whereas that in 0.01 kmol m−3 NaOH solution agrees with β-Ni(OH)2 (0001). These EC-AFM observations reveal the following orientation relationship of the surface structures on the anodic oxide layers and the substrates: NiO(110) [001] || Ni(110) [001] and NiO(110) [1\\bar10] || Ni(110) [1\\bar10] in neutral solution, and β-Ni(OH)2(0001) [11\\bar20] || Ni(110) [001] and β-Ni(OH)2(0001) [1\\bar100] || Ni(110) [1\\bar10] in alkaline solution.
