Electrodeposition of Epitaxial Co(OH)₂ on Gold and Conversion to Epitaxial CoOOH and Co₃O₄
An electrodeposition method for growing epitaxial Co(OH)2 films on single crystalline gold (111), (100), and (110) substrates is described. The films were grown by electrochemical reduction of [Co(en)3]3+ in an alkaline electrolyte. The Co(OH)2 grew with a  out-of-plane orientation on all the gold crystal orientations. The in-plane orientation follows the symmetry of the gold (111), (100), and (110) substrates. The Co(OH)2 can be converted to CoOOH by electrochemical oxidation in 1 M KOH at 95 °C, and after conversion remains epitaxial with a  out-of-plane orientation. The CoOOH film can be further converted to epitaxial Co3O4 with a  out-of-plane orientation by decomposition of the CoOOH film in air at 300 °C. This synthesis method allows for a simple fabrication of epitaxial catalysts and could be useful to probe the catalytic activity of specific crystal planes.
C. M. Hull et al., "Electrodeposition of Epitaxial Co(OH)₂ on Gold and Conversion to Epitaxial CoOOH and Co₃O₄," Journal of Materials Research, vol. 31, no. 21, pp. 3324-3331, Cambridge University Press, Nov 2016.
The definitive version is available at https://doi.org/10.1557/jmr.2016.335
Keywords and Phrases
Catalyst activity; Crystal orientation; Electrochemical oxidation; Electrodeposition; Electrodes; Electrolytes; Electrolytic reduction; Epitaxial growth; Film growth; Gold; Thin films; Alkaline electrolytes; Crystal planes; Electrochemical reductions; Electrodeposition methods; In-plane orientation; Out-of-plane orientation; Single-crystalline; Synthesis method; Cobalt
International Standard Serial Number (ISSN)
Article - Journal
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01 Nov 2016