Two-dimensional oxide derived from high-temperature liquid metals via bubble templating

Abstract

Two-dimensional (2D) oxide can be continuously produced by bubbling oxygen into liquid metals and the harvesting of these oxide relies on the proper choice of dispersion solvents. The mass-production of ligand-free 2D materials from high melting-point metals will not be possible if the limited stability of the traditional dispersion solvents is not circumvented. Herein, liquid tin was used for the first time in the bubbling protocol and 2D tin oxide was obtained in molten salts. The nanosheets were studied with combined microscopic and spectroscopic techniques, and high-density grain boundaries was identified between the sub-5-nm nano-crystallites in the nanosheets. It gives rise to the high performance in electrocatalytic CO 2 reduction reaction. Density-functional-theory based calculation was applied to achieve a deeper understanding of the relationship between the activity, selectivity, and the grainboundary features. The molten-salt based protocol could be explored for the synthesis of a library of functional 2D oxides.

Recent advances in the fabrication of 2D metal oxides

“…Owing to the weaker interactions between the liquid metal and its skin than that between the substrate and the skin, the ultrathin oxide skin can be exfoliated by contacting the liquid metal droplet with a target substrate ( Figure 8 A). Another method involves the gas injection into the liquid metal, where the interfacial oxides form at the bubble interface and the density gradients carry the oxide nanosheets into the solvent reservoir (DI water) that is placed above the molten metal ( Figure 8 B) ( Hu et al., 2021 ). And then, the obtained aqueous suspension is drop-casted onto the substrate for subsequent treatment steps.…”

Synthesis and Application of Liquid Metal Based-2D Nanomaterials: A Perspective View for Sustainable Energy

“…While most solvents become unstable at a high temperature in oxygen, molten salts are stable within a wide temperature window. In this regard, Zheng Hu et al produced 2D oxide by bubbling oxygen through the liquid metal which used the molten salts as dispersion solvent for 2D oxides ( Figure 5 d) [ 83 ]. They also recorded the polarization curve to confirm that in the CO 2 -saturated electrolyte the high activity in CO + reduction reaction over hydrogen evolution reaction ( Figure 5 e).…”

Bubble‐Mediated Mass Production of Graphene: A Review

“…Bubbles form in boiling water has attracted many applications toward the production of materials. [34,[40][41][42] For example, Ahn et al proposed an advanced boiling strategy to realize the scalable preparation of foam-like graphene networks (Figure 2c). [34] Rapid vaporization of superheated reduced graphene oxide colloids is the key factor during the process.…”

“…Bubbles form in boiling water has attracted many applications toward the production of materials. [ 34,40–42 ] For example, Ahn et al. proposed an advanced boiling strategy to realize the scalable preparation of foam‐like graphene networks (Figure 2c).…”