Controlled synthesis of 2D Mo₂C/graphene heterostructure on liquid Au substrates as enhanced electrocatalytic electrodes

Abstract

2D Mo2C has drawn considerable interest recently for its excellent properties in 2D superconductivity and enhanced hydrogen evolution reaction (HER). Liquid metals have been demonstrated to be an ideal substrate for large-area 2D Mo2C growth. However, the growth mechanism of 2D Mo2C on liquid metals has rarely been explored. Here we report the synthesis of high-quality 2D Mo2C crystals and Mo2C/graphene heterostructures on liquid Au by chemical vapor deposition method. A sunk growth mode of 2D Mo2C on liquid Au substrates has revealed, by atomic force microscope characterizations, that some Mo2C crystals grow below the level of Au terraces around tens of nanometers. Furthermore, graphene/Mo2C heterostructure is controllably synthesized by tuning the hydrogen/carbon ratio, which is proven to be an enhanced electrocatalyst for HER against pure Mo2C crystal grown on liquid Au substrates.

The tunable electric and magnetic properties of 2D MXenes and their potential applications

“…Without compromising with growth rate, Mo 2 C films in the nanometer range were achieved even at lower temperatures ∼880 o C 89 . Using the ambient pressure chemical vapor deposition method, another researcher group synthesized 2D Mo 2 C crystals and Mo 2 C/graphene heterostructures on liquid Au surface the temperature above 1100 o C under H 2 90 . The benefits of using Au instead of Cu catalyst is its lower melting point 1064 o C. The surface properties and defect concentration can be engineered through the chemical vapor deposition technique that is the advantage of this method.…”

CVD synthesis and characterization of thin Mo2C crystals

“…CVD has been a promising technique to achieve large area and high quality thin layers of Mo 2 C 3,13,22,[14][15][16][17][18][19][20][21] . In this method, Cu foil is placed on a Mo substrate and heated.…”

Low Temperature Synthesis and Growth Model of Thin Mo2C Crystals on Indium

“…For this purpose, Cahitoglu et al 15 used a liquid bimetallic Sn-Cu alloy instead of Cu foil and showed that Mo2C could grow at temperatures as low as 880 °C with sizes of μm in diameter and hundreds of nm in thickness. Sun et al 16 used Au and very recently, Young et al…”