Electron‐Beam Induced Water Removal, Phase Change, and Crystallization of Anodic‐Electrodeposited Turbostratic Nickel Hydroxide‐Oxyhydroxide. Issue 23 (4th October 2018)

• Record Type: Journal Article
• Authors: Kwan, Kin Wa; Xie, Degang; Zhang, Rongrong; Shan, Zhiwei; Ngan, Alfonso H. W.
• Is Part Of: Physica status solidi. Volume 215:Issue 23(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-10-04
• Subjects: in situ transmission electron microscopy (TEM) -- nickel hydroxide‐oxyhydroxide -- phase transformation -- turbostratic structures; Solid state physics -- Periodicals; Solids -- Industrial applications -- Periodicals; 530.41
• DOI: 10.1002/pssa.201800623
• Languages: English
• ISSNs: 1862-6300

Abstract

Abstract : Water removal, phase transformation, and crystallization of turbostratic nickel hydroxide and oxyhydroxide (Ni(OH)2 ‐NiOOH) are found to be inducible by the electron beam of a transmission electron microscope (TEM). Under 30 s of beam exposure at an accelerating voltage of 200 keV and a beam current density of 500 mA m −2, the original, characteristic turbostratic structure of Ni(OH)2 ‐NiOOH is observed to disappear, caused by the quick removal of intercalated water molecules by the electron beam. Increasing the current density from a low value of 1.5 mA m −2 to a high value of 500 mA m −2 can transform the Ni(OH)2 ‐NiOOH into nickel oxide (NiO) in 1 min. In situ heating and preheating experiments suggest that the transformation is caused by a heating effect induced by the electron beam. The results confirm that the mechanism previously discovered light‐induced actuation of Ni(OH)2 ‐NiOOH is caused by desorption of water molecules. Abstract : Water intercalated in turbostratic nickel hydroxide‐oxyhydroxide is shown to be removed by the electron beam of transmission electron microscope. Long exposure to the beam causes a transformation into nickel oxide, due to the induced thermal effect as confirmed by in situ TEM. The results explain the light‐induced actuating effect of the hydroxides and show their instability under TEM.