Synthesis of 2D cobalt oxide nanosheets using a room temperature liquid metal

Abstract

A RT liquid metal based on Ga can be used as a synthesis medium for creation of 2D nanosheets of cobalt oxide via expulsion of the sheets from the liquid metal surface into an acidic aqueous solution. The 2D nanosheets are shown to be active for OER.

Liquid Metals: A Novel Possibility of Fabricating 2D Metal Oxides

“…However, non‐favorable oxides such as CoO may form over Ga 2 O 3 via controlling the solution pH into which the material is ejected. [ 85 ] The presence of the diluted acid leads to the dissolution of any gallium oxides that are formed, subsequently promoting the formation of CoO x nanosheets in solution. Besides, Ga 2 O 3 has a similar reduction in the Gibbs free energy with TiO 2 , revealing that the surface of Ga–Ti alloy should be dominated by TiO 2 , and a few Ga 2 O 3 as a side product.…”

State-of-the-art surface oxide semiconductors of liquid metals: an emerging platform for development of multifunctional two-dimensional materials

“…The bandgap analysis of 2D ITO corroborated the optical bandgap of 3.9 eV, revealing that the developed 2D ITO is 6.25 times more transparent than the monolayer of graphene. 128,137,138 It was also found that the sheet resistivity of the 2D transparent ITO lm is a function of the ITO layer number in the lm. 128 In fact, a continuous reprinting process led to the deposition of a bilayer ITO lm with much improved conductivity.…”

“…In another research study, 2D cobalt oxide nanosheets were synthesized via injection of O 2 gas inside a liquid galinstan droplet containing various weight percentages of a cobalt alloy. 138 To prevent the formation of gallium oxide nano-akes, HCl was introduced into an aqueous solution to minimize the formation of natural surface oxide layers and to control the pH of the solution at an acidic level. 138 It is well known that acids will dissolve natural gallium oxide on the surface of a galinstan alloy containing elemental Co.…”

“…138 To prevent the formation of gallium oxide nano-akes, HCl was introduced into an aqueous solution to minimize the formation of natural surface oxide layers and to control the pH of the solution at an acidic level. 138 It is well known that acids will dissolve natural gallium oxide on the surface of a galinstan alloy containing elemental Co. The solution containing 10 mM HCl was found to be effective enough to remove the surface oxide lm of galinstan.…”

“…The solution containing 10 mM HCl was found to be effective enough to remove the surface oxide lm of galinstan. 138 The control and minimization of the formation of gallium oxide facilitate the oxidation of metallic Co in the alloy. The explosion of oxygen bubbles inside the galinstan alloy containing Co resulted in the generation of CoO 2D nanostructures.…”